feat(llm): route adapters by provider

2026-08-15 21:04:50 +00:00 · 2026-07-14 21:57:52 +08:00
parent a0359bc4a9
commit e547980d77
218 changed files with 2605 additions and 1844 deletions
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -125,7 +125,7 @@ Durability is a plugin concern. Persistence backends buffer synchronous `session

 Messages are arrays of typed content blocks (`text`, `reasoning`, `tool-call`, `tool-result`). The union derives from the merge-extensible `ContentBlockMap`; the same pattern types `MessageSource`, `FinishReason`, `TurnTrigger`, and `TurnEndReason`. New block types are coordinated across adapters, UI bridges, compaction pricing, and persistence, so block types remain a repo-wide contract.

-Streaming is a raw chunk protocol (`block-start` through `finish`) with `BlockAssembler` as the shared chunk-to-block assembler. The loop logs raw chunks while assembling them for dispatch. `LlmAdapter` is the provider seam: subclass, implement `stream()`, and register with `ctx.llm.registerAdapter(models, adapter)`. StreamChunk conventions live in [llm-streaming.md](core-data-structures/llm-streaming.md).
+Streaming uses raw chunks (`block-start` through `finish`) and `BlockAssembler`. The loop logs and assembles chunks, storing assistant provider/model provenance plus replay state. An `LlmAdapter` implements `stream()` and registers routes with `ctx.llm.registerAdapter(providers, adapter)`; requests route by `provider`, while the adapter resolves `model`. Replay state reaches a target only when both routes map to the same adapter instance, which owns validation and conversion. The contract lives in [llm-streaming.md](core-data-structures/llm-streaming.md).

 ## Extension And Composition

--- a/docs/config-catalog.md
+++ b/docs/config-catalog.md
@@ -16,6 +16,8 @@ Requires: `agents` · `sessions` · `sessionPersistence` · `tools` · `userInte
 ```ts config-catalog
 /** Plugin config: the agent template ACP sessions are created from. */
 export interface AcpConfig {
+  /** Provider route for created agents. */
+  provider?: string
  /** Model name for created agents (must have a registered adapter). */
  model?: string
  /**
@@ -37,7 +39,7 @@ Source: [`packages/ui/acp/src/index.ts:250`](../packages/ui/acp/src/index.ts)

 ```ts config-catalog
 /**
- * App config: the swappable per-deployment values. `model` configures the
+ * App config: the swappable per-deployment values. `provider` and `model` configure the
 * agent template the ACP bridge creates each session's agent from (NOT a
 * pre-created agent — ACP creates agents at `session/new`); `persona` is the
 * deployment persona (forwarded to the system-prompt plugin); `toolOrder` is
@@ -46,6 +48,8 @@ Source: [`packages/ui/acp/src/index.ts:250`](../packages/ui/acp/src/index.ts)
 * through agent-core); `persistenceRoot` is the JSONL backend's directory.
 */
 export interface Config {
+  /** Provider route for ACP-created agents. */
+  provider: string
  /** Model name for ACP-created agents (must have a registered adapter). */
  model: string
  /** Deployment persona (the system-prompt plugin's `persona` config). */
@@ -234,7 +238,9 @@ export interface BasicCompactConfig {
  thresholdRatio: number
  /** Number of tokens of recent context to retain during compaction. */
  retainTokens: number
-  /** Model to use for summarization (`''` — uses the agent's model). */
+  /** Provider to use for summarization (`''` with an empty model inherits the conversation target). */
+  summarizationProvider: string
+  /** Model to use for summarization (`''` with an empty provider inherits the conversation target). */
  summarizationModel: string
  /** Provider generation cap for the summarization call. */
  maxTokens: number
@@ -380,8 +386,6 @@ export interface Config {
  apiKey?: string
  /** Endpoint base; falls back to $DEEPSEEK_BASE_URL, then the public API. */
  baseURL?: string
-  /** Model names to register (sent verbatim on the wire). */
-  models?: string[]
  /** Thinking-mode default for every request (provider default: enabled). */
  thinking?: 'enabled' | 'disabled'
  /** Thinking effort (only meaningful with thinking enabled). */
@@ -389,38 +393,51 @@ export interface Config {
 }
 ```

-Source: [`packages/llm/llm-deepseek/src/index.ts:43`](../packages/llm/llm-deepseek/src/index.ts)
+Source: [`packages/llm/llm-deepseek/src/index.ts:42`](../packages/llm/llm-deepseek/src/index.ts)

 ## `@deepseek-ai/dsh-llm-pi-ai`

 Requires: `llm`

 ```ts config-catalog
-/**
- * Plugin config, validated by the same-named schemastery schema. Every field
- * is optional in yml: credentials/endpoint fall back to the environment (a
- * missing API key fails plugin load, not the first call).
- */
+/** Plugin configuration: the non-empty provider profiles this instance owns. */
 export interface Config {
-  /** API key; falls back to $DEEPSEEK_API_KEY. Required one way or the other. */
-  apiKey?: string
-  /** Endpoint base; falls back to $DEEPSEEK_BASE_URL, then the public API. */
-  baseURL?: string
-  /** Model names to register (sent verbatim on the wire). */
-  models?: string[]
-  /**
-   * Thinking level for every request: 'off' disables thinking mode; 'high'
-   * and 'xhigh' (wire 'max') set the effort. Omitted = provider default
-   * (thinking enabled), matching llm-deepseek's omission semantics.
-   */
-  reasoning?: PiAiReasoning
+  /** Non-empty set of pi-ai provider routes this adapter instance owns. */
+  providers: PiAiProviderProfile[]
 }

-/** Reasoning levels surfaced by this adapter (DeepSeek wire: high|max). */
-export type PiAiReasoning = 'off' | 'high' | 'xhigh'
+/** Configuration for one pi-ai provider route. */
+export interface PiAiProviderProfile {
+  /** pi-ai provider catalog name and Harness route key. */
+  provider: string
+  /** Provider credential; when absent pi-ai uses its provider-native ambient discovery. */
+  apiKey?: string
+  /** Override the selected catalog model's endpoint without changing its protocol metadata. */
+  baseURL?: string
+  /** Provider request headers; Harness attribution wins reserved names. */
+  headers?: Record<string, string>
+  /** Provider-neutral pi-ai reasoning level. */
+  reasoning?: ThinkingLevel
+  /** Token budgets used by reasoning providers that support them. */
+  thinkingBudgets?: ThinkingBudgets
+  /** Prompt-cache retention preference. */
+  cacheRetention?: CacheRetention
+  /** Streaming transport preference. */
+  transport?: Transport
+  /** HTTP/provider SDK timeout in milliseconds. */
+  timeoutMs?: number
+  /** WebSocket connection timeout in milliseconds. */
+  websocketConnectTimeoutMs?: number
+  /** Provider SDK retry count. */
+  maxRetries?: number
+  /** Maximum provider-requested retry delay in milliseconds. */
+  maxRetryDelayMs?: number
+}
 ```

-Source: [`packages/llm/llm-pi-ai/src/index.ts:37`](../packages/llm/llm-pi-ai/src/index.ts)
+Depends on: `CacheRetention` (`@earendil-works/pi-ai`) · `ThinkingBudgets` (`@earendil-works/pi-ai`) · `ThinkingLevel` (`@earendil-works/pi-ai`) · `Transport` (`@earendil-works/pi-ai`)
+
+Source: [`packages/llm/llm-pi-ai/src/config.ts:40`](../packages/llm/llm-pi-ai/src/config.ts)

 ## `@deepseek-ai/dsh-llm-replay`

@@ -611,7 +628,7 @@ Source: [`packages/skill/skill-local/src/index.ts:39`](../packages/skill/skill-l
 ```ts config-catalog
 /**
 * App config: the swappable per-demo values, each routed to where the app wires
- * it. `model`/`resumeSessionId` configure the pre-created `main` agent (through
+ * it. `provider`/`model`/`resumeSessionId` configure the pre-created `main` agent (through
 * {@link @deepseek-ai/dsh-agent-core}'s forwarded `agents` list); `persona` is
 * the deployment persona (forwarded to the system-prompt plugin); `toolOrder`
 * is the explicit model-facing tool order (forwarded to the system-prompt plugin);
@@ -620,6 +637,8 @@ Source: [`packages/skill/skill-local/src/index.ts:39`](../packages/skill/skill-l
 * `welcome` is the UI banner.
 */
 export interface Config {
+  /** Provider route for the `main` agent. */
+  provider: string
  /** Model name for the `main` agent (must have a registered adapter). */
  model: string
  /** Deployment persona (the system-prompt plugin's `persona` config). */
--- a/docs/cookbook/adding-an-llm-adapter.md
+++ b/docs/cookbook/adding-an-llm-adapter.md
@@ -14,11 +14,11 @@ export const inject = ['llm']
 export const Config: z<Config> = z.object({ apiKey: z.string(), … })

 export function apply(ctx: Context, config: Config) {
-  ctx.llm.registerAdapter(['model-a', 'model-b'], new MyAdapter(…))
+  ctx.llm.registerAdapter(['my-provider'], new MyAdapter(…))
 }
 ```

-Registration is effect-based (HMR-safe); one adapter per model name — duplicates throw. Secrets are cordis-native: schemastery Config with env fallbacks, fed from cordis.yml via `!!js process.env.MY_KEY`. Never read ad-hoc key files in code.
+Registration is effect-based (HMR-safe); one adapter per provider route — duplicates throw, and multi-route registration is all-or-nothing. `options.provider` selects the adapter and `options.model` is the provider model id, so a dynamic catalog adapter can serve new models without lifecycle reconfiguration. Secrets are cordis-native: schemastery Config with env fallbacks, fed from cordis.yml via `!!js process.env.MY_KEY`. Never read ad-hoc key files in code.

 ## Protocol obligations (the contract two implementations verified)

@@ -28,6 +28,7 @@ Registration is effect-based (HMR-safe); one adapter per model name — duplicat
 - Errors have exactly two sanctioned paths: THROW from `stream()` (transport and protocol failures — use `LlmError` with a stable code), or end the stream with `finish {kind: 'error' | 'aborted'}` (provider in-band failures). Consumers handle both; pick per failure class and document it.
 - Honor `options.signal` (pass it to fetch / your SDK).
 - A `GenerateOptions` field your provider cannot honor (e.g. a `stop` list on a provider without stop sequences): throw `LlmError(..., 'UNSUPPORTED')` rather than silently dropping it.
+- If the provider requires response ids, signatures, or other native metadata on follow-up calls, emit the minimal lossless-JSON projection as `finish.replayState`. Validate it when rebuilding history. `LlmService` passes it only when the historical provider route and target provider route are currently owned by the exact same adapter instance; your adapter decides whether same-model, cross-model, or cross-provider restoration is legal. Never infer native replay from provider/model names alone when state is absent.

 Provider-specific request knobs (thinking modes, effort levels) belong in the ADAPTER's Config, not in `GenerateOptions` — the core vocabulary stays provider-neutral.

@@ -39,5 +40,5 @@ Split the adapter into testable stages (llm-deepseek's layout): wire types (`typ

 - **Unit: mock the provider, not the harness.** A scripted `node:http` server speaking the provider's wire format covers happy paths, every error status, malformed payloads, premature closes, and aborts — no network, and it drives the 100% per-file coverage gate. Works for SDK-backed adapters too (point the SDK's baseURL at the mock).
 - **Hostile framing tests.** Split stream payloads at arbitrary byte positions (including mid-UTF-8) — real networks do.
- **E2E: `tests/*.e2e.ts`** under `pnpm run test:e2e`, gated with `describe.skipIf(!process.env.MY_KEY)` so CI (no secrets) stays green. Cover each model × each provider mode you map (thinking on/off, effort levels), a tool-call round trip INCLUDING the follow-up turn with results in history, and loose assertions only (substring/structure, bounded maxTokens — real models are nondeterministic).
+- **E2E: `tests/*.e2e.ts`** under `pnpm run test:e2e`, gated with `describe.skipIf(!process.env.MY_KEY)` so CI (no secrets) stays green. Cover representative model/provider/API families and every provider mode you map, a tool-call round trip INCLUDING the follow-up turn with results in history, and loose assertions only (substring/structure, bounded maxTokens — real models are nondeterministic).
 - Register the e2e file pattern in `knip.json` (per-workspace `entry` override) or knip flags it unused.
--- a/docs/cordis-catalog/events.md
+++ b/docs/cordis-catalog/events.md
@@ -23,7 +23,7 @@ An agent's fully composed scoped world was published in the AgentRegistry. Its s

 Types: [Agent](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:316`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:318`](../../packages/core/agent/src/types.ts)

 ### `agent/disposed` — emit

@@ -35,7 +35,7 @@ An agent was removed from the registry. The concrete AgentLoop lifecycle emits t

 Types: [Agent](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:331`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:333`](../../packages/core/agent/src/types.ts)

 ### `agent/error` — emit

@@ -47,7 +47,7 @@ A step or turn errored. The loop reports a failure here (plus the logger) even w

 Types: [Agent](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:605`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:607`](../../packages/core/agent/src/types.ts)

 ### `agent/pre-step` — serial

@@ -61,7 +61,7 @@ Serial (awaited in registration order), not a waterfall: a listener mutates the

 Types: [Agent](../core-data-structures/core.md) · [Message](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:438`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:440`](../../packages/core/agent/src/types.ts)

 ### `agent/prompt-submit` — waterfall

@@ -73,7 +73,7 @@ Waterfall: decide what happens to ONE drained queued message before it becomes a

 Types: [Agent](../core-data-structures/core.md) · [ContentBlock](../core-data-structures/core.md) · [MessageSource](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:456`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:458`](../../packages/core/agent/src/types.ts)

 ### `agent/queued` — emit

@@ -85,7 +85,7 @@ A message entered the agent's inbox (queued or steering). Content and the resolv

 Types: [Agent](../core-data-structures/core.md) · [ContentBlock](../core-data-structures/core.md) · [MessageSource](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:360`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:362`](../../packages/core/agent/src/types.ts)

 ### `agent/request` — waterfall

@@ -97,7 +97,7 @@ Waterfall: shape the step's call configuration — model switching, sampling ove

 Types: [Agent](../core-data-structures/core.md) · [LlmCallConfig](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:485`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:487`](../../packages/core/agent/src/types.ts)

 ### `agent/session-prefix` — waterfall

@@ -113,7 +113,7 @@ The seed is a frozen empty list; a contributing listener returns a NEW array —

 Types: [Agent](../core-data-structures/core.md) · [Message](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:537`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:539`](../../packages/core/agent/src/types.ts)

 ### `agent/session-start` — emit

@@ -125,7 +125,7 @@ The agent's session lifecycle began, fired once before its first turn. `source`

 Types: [Agent](../core-data-structures/core.md) · [SessionStartSource](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:381`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:383`](../../packages/core/agent/src/types.ts)

 ### `agent/status` — emit

@@ -137,7 +137,7 @@ Agent status changed (`idle` ⇄ `running`, or → `disposed`). Drive lifecycle

 Types: [Agent](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:345`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:347`](../../packages/core/agent/src/types.ts)

 ### `agent/step-result` — waterfall

@@ -149,7 +149,7 @@ Waterfall: post-process the assembled assistant Message before tool dispatch (va

 Types: [Agent](../core-data-structures/core.md) · [Message](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:552`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:554`](../../packages/core/agent/src/types.ts)

 ### `agent/turn-continuation` — waterfall

@@ -161,7 +161,7 @@ Waterfall: override the turn-continuation decision via a typed ContinuationDecis

 Types: [Agent](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:570`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:572`](../../packages/core/agent/src/types.ts)

 ### `agent/turn-stop` — serial

@@ -173,7 +173,7 @@ Serial terminal-stop checkpoint after the ordinary `agent/turn-continuation` wat

 Types: [Agent](../core-data-structures/core.md)

-Source: [`packages/core/agent/src/types.ts:588`](../../packages/core/agent/src/types.ts)
+Source: [`packages/core/agent/src/types.ts:590`](../../packages/core/agent/src/types.ts)

 ## `approval/*`

@@ -239,7 +239,7 @@ Waterfall around every streaming model call (retry, replay, routing). Bound to t

 Types: [GenerateOptions](../core-data-structures/core.md) · [StreamChunk](../core-data-structures/llm-streaming.md)

-Source: [`packages/llm/llm/src/index.ts:39`](../../packages/llm/llm/src/index.ts)
+Source: [`packages/llm/llm/src/index.ts:40`](../../packages/llm/llm/src/index.ts)

 ## `session/*`

--- a/docs/cordis-catalog/services.md
+++ b/docs/cordis-catalog/services.md
@@ -152,14 +152,14 @@ Source: [`packages/fs/fs/src/index.ts:172`](../../packages/fs/fs/src/index.ts)
 The abstract `llm` service: an adapter registry plus a streaming model-call surface, interceptable via the `llm/stream` waterfall.

 ```ts cordis-catalog
-registerAdapter(models: string[], adapter: LlmAdapter): () => void
-models(): string[]
+registerAdapter(providers: string[], adapter: LlmAdapter): () => void
+providers(): string[]
 stream(options: GenerateOptions): AsyncIterable<StreamChunk>
 ```

 Types: [GenerateOptions](../core-data-structures/core.md) · [StreamChunk](../core-data-structures/llm-streaming.md)

-Source: [`packages/llm/llm/src/index.ts:88`](../../packages/llm/llm/src/index.ts)
+Source: [`packages/llm/llm/src/index.ts:89`](../../packages/llm/llm/src/index.ts)

 ## `ctx.sandbox` — `SandboxProvider` (abstract seam)

@@ -218,7 +218,7 @@ list(): Session[]
 fork(source: SessionForkSource, boundary?: number, childSessionId?: SessionId): Session
 ```

-Source: [`packages/core/session/src/index.ts:590`](../../packages/core/session/src/index.ts)
+Source: [`packages/core/session/src/index.ts:617`](../../packages/core/session/src/index.ts)

 ## `ctx.skills` — `SkillService`

--- a/docs/core-data-structures/compaction.md
+++ b/docs/core-data-structures/compaction.md
@@ -11,7 +11,7 @@ Compaction extends [`SessionEventMap`](session.md) with three event types via de
 | Event | Payload | Role |
 |---|---|---|
 | `compact/start` | `{ turn }` | acquires the log-recorded lock |
-| `compact/summary` | `{ summary, shadowedRange, shadowedSeqs, shadowedTokenCount, model, maxTokens? }` | provenance: the summary blocks, the shadowed surface-boundary pair (`start`/`end` seqs — a position span, not a numeric interval), the shadowed seqs in surface order, the estimated token count, and the summarize call's envelope (`model`, plus its generation cap when one applied) — logged so the one-shot request is reconstructable from log + code (the reconstructability RFC) |
+| `compact/summary` | `{ summary, shadowedRange, shadowedSeqs, shadowedTokenCount, provider, model, maxTokens? }` | provenance: the summary blocks, the shadowed surface-boundary pair (`start`/`end` seqs — a position span, not a numeric interval), the shadowed seqs in surface order, the estimated token count, and the summarize call's envelope (`provider`, `model`, plus its generation cap when one applied) — logged so the one-shot request is reconstructable from log + code (the reconstructability RFC) |
 | `compact/end` | `{ turn, error? }` | releases the lock (`error` set when summarization threw) |

 The lock brackets the **whole** operation: `compact/start` is appended first, then summarization, the `compact/summary` provenance record, and the `user/message` replacement all land, and only then `compact/end`. Releasing the lock last turns a crash mid-operation into a detectable orphaned lock (a `compact/start` with no matching `compact/end`) rather than a `compact/end` that falsely claims compaction finished.
--- a/docs/core-data-structures/core.md
+++ b/docs/core-data-structures/core.md
@@ -102,12 +102,29 @@ interface ContentBlockMap {

 The block interfaces (full fields in source): `TextBlock` (`text`), `ReasoningBlock` (thinking, distinct from visible text), `ToolCallBlock` (`id: CallId`, `name`, raw-JSON `arguments`), `ToolResultBlock` (`toolCallId`, nested `content: ContentBlock[]`, `isError?`). `ContentBlock = ContentBlockMap[ContentBlockType]`. The core set is limited to blocks every shipping path honors — multimodal content (images, audio, …) has no core block type; a feature that needs one adds it via the merge-extensible map together with the adapter/UI/compaction support that honors it.

-A `Message` is a role plus blocks:
+A `Message` is a role plus blocks. Loop-derived assistant messages carry their durable provider/model identity and optional adapter-private replay metadata:
+
+```ts type-equiv
+interface AssistantProvenance {
+  /** Provider route that produced the message. */
+  provider: string
+  /** Provider model id that produced the message. */
+  model: string
+  /**
+   * Lossless-JSON adapter state needed to replay the provider response.
+   * `LlmService` exposes it to a target adapter only when that adapter instance
+   * currently owns both this historical provider and the target provider.
+   */
+  replayState?: unknown
+}
+```

 ```ts type-equiv
 interface Message {
  role: 'system' | 'user' | 'assistant'
  content: ContentBlock[]
+  /** Present only on assistant messages produced by a routed adapter. */
+  provenance?: AssistantProvenance
 }
 ```

@@ -134,6 +151,8 @@ Source: [`packages/llm/llm/src/types.ts`](../../packages/llm/llm/src/types.ts)

 ```ts type-equiv
 interface GenerateOptions {
+  /** Registered provider route selecting the adapter instance. */
+  provider: string
  model: string
  /**
   * Ordered conversation messages, exactly as the provider sees them (after
@@ -201,7 +220,7 @@ The model-facing `ToolSchema` is the wire shape; the registered `ToolDefinition`

 ### The request envelope: `LlmCallConfig` and the logged header

-Requests are built by the loop, not shaped per call: the non-history half of a request — the `EpochHeader`: this call configuration plus the rendered system prompt, the tool schemas in the authoritative returned assembly order (initially canonicalized by dsh-system-prompt's `toolOrder` config, or lexicographically when unset), and the session prefix — is logged session state (`request/header` snapshot and delta events, [session.md](session.md#the-request-header-events-requestheader-and-requestheader-delta)), so every conversation request is a pure function of the session log ([reconstructability RFC](../rfc/implemented/architecture/2026-07-05-reconstructable-requests.md)). The `agent/request` waterfall receives a frozen `LlmCallConfig` seed and a listener returns a replacement to switch model or sampling; the `agent/session-prefix` waterfall — fired once per loop instance — composes the request-only messages fronting the derived history (recorded as the header's `messagePrefix`) — the loop logs whatever the request actually uses. Loop-built requests arrive at `llm/stream` deep-frozen; mutation throws.
+Requests are built by the loop, not shaped per call: the non-history half of a request — the `EpochHeader`: this call configuration plus the rendered system prompt, the tool schemas in the authoritative returned assembly order (initially canonicalized by dsh-system-prompt's `toolOrder` config, or lexicographically when unset), and the session prefix — is logged session state (`request/header` snapshot and delta events, [session.md](session.md#the-request-header-events-requestheader-and-requestheader-delta)), so every conversation request is a pure function of the session log ([reconstructability RFC](../rfc/implemented/architecture/2026-07-05-reconstructable-requests.md)). The `agent/request` waterfall receives a frozen `LlmCallConfig` seed and a listener returns a replacement to switch provider, model, or sampling; the `agent/session-prefix` waterfall — fired once per loop instance — composes the request-only messages fronting the derived history (recorded as the header's `messagePrefix`) — the loop logs whatever the request actually uses. Loop-built requests arrive at `llm/stream` deep-frozen; mutation throws.

 On the wire, a loop-built request reads in this order: the `system` slot (the rendered prompt assembly) → `messagePrefix` (the frozen session prefix) → the derived history — the boundary snapshot, whose tail is the newest `user/message` on a turn's first step and the previous step's tool results on later steps. The prefix never enters the derived history; its durable record is the header events, and the dev invariant recomputes exactly this equation against every loop-built request.

@@ -209,6 +228,7 @@ FIXME(call-config-shape): revisit the exact definition of this type — which fi

 ```ts type-equiv
 interface LlmCallConfig {
+  provider: string
  model: string
  temperature?: number
  maxTokens?: number
@@ -353,7 +373,7 @@ interface Agent {
 }
 ```

-`AgentStatus` is `'idle' | 'running' | 'disposed'`. `AgentId` is a branded string. `AgentOptions` (`model?`) is merge-extensible — plugins add creation options by declaration merging. Persona is not an agent option: the `dsh-system-prompt` config supplies the global default, and an agent-scoped `deployment:persona` section may shadow it. The `agent/*` event taxonomy (lifecycle emits incl. `agent/session-start`, serial `agent/pre-step`/`agent/turn-stop` checkpoints, and the `agent/prompt-submit`/`agent/request`/`agent/session-prefix`/`agent/step-result`/`agent/turn-continuation` waterfalls) is in [architecture.md § Event taxonomy](../architecture.md#event-taxonomy); turn/step boundaries are durable `session/event` records, not `agent/*` emits.
+`AgentStatus` is `'idle' | 'running' | 'disposed'`. `AgentId` is a branded string. `AgentOptions` (`provider?`, `model?`) is merge-extensible — plugins add creation options by declaration merging. A model dispatch requires both route fields after the `agent/request` waterfall. Persona is not an agent option: the `dsh-system-prompt` config supplies the global default, and an agent-scoped `deployment:persona` section may shadow it. The `agent/*` event taxonomy (lifecycle emits incl. `agent/session-start`, serial `agent/pre-step`/`agent/turn-stop` checkpoints, and the `agent/prompt-submit`/`agent/request`/`agent/session-prefix`/`agent/step-result`/`agent/turn-continuation` waterfalls) is in [architecture.md § Event taxonomy](../architecture.md#event-taxonomy); turn/step boundaries are durable `session/event` records, not `agent/*` emits.

 ## Interception decisions

--- a/docs/core-data-structures/llm-streaming.md
+++ b/docs/core-data-structures/llm-streaming.md
@@ -16,7 +16,12 @@ type StreamChunk =
  | { type: 'tool-call-delta'; index: number; id: CallId; name?: string; argumentsDelta: string }
  | { type: 'block-end'; index: number; block: ContentBlock }
  | { type: 'usage'; usage: TokenUsage }
-  | { type: 'finish'; reason: FinishReason }
+  | {
+    type: 'finish'
+    reason: FinishReason
+    /** Adapter-private lossless-JSON state for replaying a successful response. */
+    replayState?: unknown
+  }
 ```

 ## The adapter contract
@@ -27,8 +32,9 @@ Every adapter MUST obey these, and every consumer may rely on them:
 - **Tool-call `arguments` stay raw JSON strings end-to-end.** Partial fragments stream via `argumentsDelta`; a provider that hands back parsed objects re-stringifies at `block-end`.
 - **Two sanctioned error paths.** A failure may either THROW from `stream()` (transport/protocol errors) **or** end the stream with `finish {kind:'error'|'aborted'}` (provider in-band errors, for adapters that can't throw mid-stream). Consumers must handle *both*. The agent loop translates a finish-error/aborted into a turn error — it never logs a normal completed assistant message for a failed step.
 - **Every provider HTTP request carries the app-attribution header.** Adapters send `attributionHeaders()` (below) - the `User-Agent` baseline - and prove it with a wire-level test (mock server asserting the received header, or the library's header hook for a library-backed adapter).
+- **Replay state is adapter-owned.** A successful `finish` may carry lossless-JSON state needed to reconstruct a native provider response. The loop stores it with the assembled assistant message unless an `agent/step-result` listener rewrote the content. On a later request, `LlmService` passes the state only when the historical provider and target provider are currently registered to the exact same adapter instance. That adapter validates the state and owns any cross-model or cross-provider conversion; other adapters receive the provider-neutral content and provenance without the private state.

-This contract is why two adapters exist as a deliberate pair: `dsh-llm-deepseek` (hand-rolled fetch/SSE) and `dsh-llm-pi-ai` (the same endpoint through `@earendil-works/pi-ai`). Two independent internals over one contract is what pinned the protocol down — the library-backed adapter can't throw mid-stream, so it exercises the finish-chunk error path the hand-rolled one might not.
+This contract was pinned down by two deliberately independent implementations: `dsh-llm-deepseek` (hand-rolled fetch/SSE) and `dsh-llm-pi-ai` (a generic multi-provider adapter through `@earendil-works/pi-ai`). The library-backed adapter cannot throw mid-stream, so it exercises the finish-chunk error path the hand-rolled one might not.

 ## `AppIdentity` — app attribution

@@ -58,11 +64,11 @@ interface TokenUsage {

 ## `BlockAssembler`

-`BlockAssembler` ([`packages/llm/llm/src/assembler.ts`](../../packages/llm/llm/src/assembler.ts)) is the single shared implementation that folds a `StreamChunk` stream back into `ContentBlock`s and a final `Message`. The loop logs the raw chunks (for replay fidelity) while feeding the same chunks through an assembler — so the canonical log keeps token-level detail and the derived message is rebuilt deterministically. A consumer that needs the assembled result without re-implementing the fold uses this.
+`BlockAssembler` ([`packages/llm/llm/src/assembler.ts`](../../packages/llm/llm/src/assembler.ts)) is the single shared implementation that folds a `StreamChunk` stream back into `ContentBlock`s, usage, finish reason, and replay state. The loop logs the raw chunks while feeding the same chunks through an assembler, then stores the assembled assistant content with its provider/model provenance. A consumer that needs the assembled result without re-implementing the fold uses this.

 ## The seam

-`LlmAdapter` is the provider seam: subclass, implement `stream()`, register with `ctx.llm.registerAdapter(models, adapter)`. The `block-start` / `block-end` `index` correlation and the assembler together mean an adapter only has to emit well-formed chunks — block reassembly is not each adapter's problem. The consumer surface (`ctx.llm.stream()`) and the `llm/stream` waterfall are described in [architecture.md § Content blocks and streaming](../architecture.md#content-blocks-and-streaming-dsh-llm).
+`LlmAdapter` is the provider seam: subclass, implement `stream()`, and register one adapter instance with `ctx.llm.registerAdapter(providers, adapter)`. `GenerateOptions.provider` selects the registered adapter; `GenerateOptions.model` is passed to that adapter and need not be registered at lifecycle start. Duplicate provider routes fail atomically. Adapter lookup happens at the terminal continuation of the `llm/stream` waterfall, so a listener may short-circuit the call or route a mutable one-shot request before lookup. The `block-start` / `block-end` `index` correlation and the assembler together mean an adapter only has to emit well-formed chunks — block reassembly is not each adapter's problem. The consumer surface (`ctx.llm.stream()`) and the `llm/stream` waterfall are described in [architecture.md § Content blocks and streaming](../architecture.md#content-blocks-and-streaming-dsh-llm).

 `ContentBlockType` (the key set the `index`-correlated blocks carry) derives from `ContentBlockMap`:

--- a/docs/core-data-structures/session.md
+++ b/docs/core-data-structures/session.md
@@ -41,7 +41,7 @@ interface SessionEventMap {
   * the model output and its accounting travel together (there is no separate
   * usage record). `usage` is absent when the adapter reported none.
   */
-  'assistant/message': { turn: number; step: number; content: ContentBlock[]; usage?: TokenUsage }
+  'assistant/message': { turn: number; step: number; content: ContentBlock[]; provenance: AssistantProvenance; usage?: TokenUsage }
  'tool/call': { turn: number; step: number; callId: CallId; name: string; arguments: string }
  'tool/result': { turn: number; step: number; callId: CallId; content: ContentBlock[]; isError: boolean; error?: { name: string; code: string }; meta?: unknown }
  /** Steering content injected between steps of a running turn. */
@@ -103,7 +103,7 @@ The request envelope — the `EpochHeader` (call config + rendered system prompt

 ```ts type-equiv
 export interface EpochHeader {
-  /** The conversation's call configuration (model + sampling scalars). */
+  /** The conversation's call configuration (provider + model + sampling scalars). */
  config: LlmCallConfig
  /** Rendered system prompt text; absent for a system-less request. */
  system?: string
@@ -201,11 +201,11 @@ export interface SurfaceNode {
 `Session.deriveMessages()` projects the event log into the `Message[]` the model sees — cached (each surface node projected once, when first seen; a surface rewrite rebuilds) and frozen (a fresh array per call over shared, deep-frozen messages, so mutating logged history through a projection is unrepresentable). `deriveEventMessage(event)` is the per-node pure function the fold applies — public so external reconstructors and the dev invariant project a log prefix with exactly the same rules and cannot disagree with the cache. The projection rules:

 - `user/message` → a user message.
- `assistant/message` → an assistant message. Raw `assistant/chunk` events are replay/UI data and are **skipped** in derivation (the assembled message is authoritative). An **empty-content** `assistant/message` is also skipped — a max-tokens step cut off with no content still records an `assistant/message` to host its `usage`, but a content-less assistant turn must not enter the provider transcript.
+- `assistant/message` → an assistant message with the event's provider/model provenance and optional adapter-private replay state. Raw `assistant/chunk` events are replay/UI data and are **skipped** in derivation (the assembled message is authoritative). An **empty-content** `assistant/message` is also skipped — a max-tokens step cut off with no content still records an `assistant/message` to host its usage/provenance, but a content-less assistant turn must not enter the provider transcript.
 - `tool/result` → a user message carrying a `tool-result` block.
 - `context/message`, `steering/message` → user-role messages wrapped in a tagged envelope (`<context source="…">…</context>`) at their chronological position — the "system-reminder" pattern; the model distinguishes them from real prompts by the envelope.

-Everything else (`turn/*`, `step/*`) is structural and does not project into a message. Token usage is observed on `assistant/message.usage` (the step that produced it); an operational error's step number is on `turn/end.reason` for `kind: 'error'`.
+Everything else (`turn/*`, `step/*`) is structural and does not project into a message. Token usage is observed on `assistant/message.usage` (the step that produced it); an operational error's step number is on `turn/end.reason` for `kind: 'error'`. Because this unreleased format intentionally has no compatibility promise, seed/load validation rejects request headers without provider+model and assistant messages without provider/model provenance instead of guessing a route for historical data.

 ## Live-session fork API

--- a/docs/event-producer-consumer.md
+++ b/docs/event-producer-consumer.md
@@ -7,24 +7,24 @@ This matrix shows which packages dispatch each harness-owned event and which pac

 | Event | Mode | Declared in | Dispatchers | Listeners |
 | --- | --- | --- | --- | --- |
-| `agent/created` | `emit` | [`packages/core/agent/src/types.ts:316`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`jsonrpc`](../packages/ui/jsonrpc), [`stdio-agent`](../packages/ui/stdio-agent) |
-| `agent/disposed` | `emit` | [`packages/core/agent/src/types.ts:331`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`stdio-agent`](../packages/ui/stdio-agent) |
-| `agent/error` | `emit` | [`packages/core/agent/src/types.ts:605`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | - |
-| `agent/pre-step` | `serial` | [`packages/core/agent/src/types.ts:438`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`compact-basic`](../packages/compact/compact-basic), [`user-approval`](../packages/ui/user-approval) |
-| `agent/prompt-submit` | `waterfall` | [`packages/core/agent/src/types.ts:456`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`acp`](../packages/ui/acp), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard) |
-| `agent/queued` | `emit` | [`packages/core/agent/src/types.ts:360`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | - |
-| `agent/request` | `waterfall` | [`packages/core/agent/src/types.ts:485`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | - |
-| `agent/session-prefix` | `waterfall` | [`packages/core/agent/src/types.ts:537`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`tool-skill`](../packages/skill/tool-skill) |
-| `agent/session-start` | `emit` | [`packages/core/agent/src/types.ts:381`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`invariants`](../packages/support/invariants) |
-| `agent/status` | `emit` | [`packages/core/agent/src/types.ts:345`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`invariants`](../packages/support/invariants), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard), [`stdio-agent`](../packages/ui/stdio-agent) |
-| `agent/step-result` | `waterfall` | [`packages/core/agent/src/types.ts:552`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | - |
-| `agent/turn-continuation` | `waterfall` | [`packages/core/agent/src/types.ts:570`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) |
-| `agent/turn-stop` | `serial` | [`packages/core/agent/src/types.ts:588`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`subagent-inprocess`](../packages/subagent/subagent-inprocess) |
+| `agent/created` | `emit` | [`packages/core/agent/src/types.ts:318`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`jsonrpc`](../packages/ui/jsonrpc), [`stdio-agent`](../packages/ui/stdio-agent) |
+| `agent/disposed` | `emit` | [`packages/core/agent/src/types.ts:333`](../packages/core/agent/src/types.ts) | [`agent`](../packages/core/agent) (`events.dispatch`) | [`stdio-agent`](../packages/ui/stdio-agent) |
+| `agent/error` | `emit` | [`packages/core/agent/src/types.ts:607`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | - |
+| `agent/pre-step` | `serial` | [`packages/core/agent/src/types.ts:440`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`compact-basic`](../packages/compact/compact-basic), [`user-approval`](../packages/ui/user-approval) |
+| `agent/prompt-submit` | `waterfall` | [`packages/core/agent/src/types.ts:458`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`acp`](../packages/ui/acp), [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard) |
+| `agent/queued` | `emit` | [`packages/core/agent/src/types.ts:362`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | - |
+| `agent/request` | `waterfall` | [`packages/core/agent/src/types.ts:487`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | - |
+| `agent/session-prefix` | `waterfall` | [`packages/core/agent/src/types.ts:539`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`tool-skill`](../packages/skill/tool-skill) |
+| `agent/session-start` | `emit` | [`packages/core/agent/src/types.ts:383`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex), [`invariants`](../packages/support/invariants) |
+| `agent/status` | `emit` | [`packages/core/agent/src/types.ts:347`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`emit`) | [`invariants`](../packages/support/invariants), [`repeat-tool-guard`](../packages/guard/repeat-tool-guard), [`stdio-agent`](../packages/ui/stdio-agent) |
+| `agent/step-result` | `waterfall` | [`packages/core/agent/src/types.ts:554`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | - |
+| `agent/turn-continuation` | `waterfall` | [`packages/core/agent/src/types.ts:572`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`waterfall`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`hooks-codex`](../packages/hooks/hooks-codex) |
+| `agent/turn-stop` | `serial` | [`packages/core/agent/src/types.ts:590`](../packages/core/agent/src/types.ts) | [`agent-loop`](../packages/core/agent-loop) (`serial`) | [`subagent-inprocess`](../packages/subagent/subagent-inprocess) |
 | `approval/request` | `waterfall` | [`packages/ui/user-approval/src/index.ts:70`](../packages/ui/user-approval/src/index.ts) | [`user-approval`](../packages/ui/user-approval) (`waterfall`) | [`acp`](../packages/ui/acp) |
 | `fs/edit-intent` | `waterfall` | [`packages/fs/fs/src/index.ts:123`](../packages/fs/fs/src/index.ts) | [`tool-fs`](../packages/fs/tool-fs) (`waterfall`) | [`fs-policy`](../packages/fs/fs-policy) |
 | `fs/observed` | `emit` | [`packages/fs/fs/src/index.ts:138`](../packages/fs/fs/src/index.ts) | [`tool-fs`](../packages/fs/tool-fs) (`emit`) | [`fs-policy`](../packages/fs/fs-policy) |
 | `fs/write-intent` | `waterfall` | [`packages/fs/fs/src/index.ts:109`](../packages/fs/fs/src/index.ts) | [`tool-fs`](../packages/fs/tool-fs) (`waterfall`) | [`fs-policy`](../packages/fs/fs-policy) |
-| `llm/stream` | `waterfall` | [`packages/llm/llm/src/index.ts:39`](../packages/llm/llm/src/index.ts) | [`llm`](../packages/llm/llm) (`waterfall`) | [`invariants`](../packages/support/invariants), [`llm-replay`](../packages/support/llm-replay) |
+| `llm/stream` | `waterfall` | [`packages/llm/llm/src/index.ts:40`](../packages/llm/llm/src/index.ts) | [`llm`](../packages/llm/llm) (`waterfall`) | [`invariants`](../packages/support/invariants), [`llm-replay`](../packages/support/llm-replay) |
 | `session/created` | `emit` | [`packages/core/session/src/index.ts:52`](../packages/core/session/src/index.ts) | [`session`](../packages/core/session) (`events.dispatch`) | [`invariants`](../packages/support/invariants), [`jsonrpc`](../packages/ui/jsonrpc), [`session-persistence`](../packages/session-persistence/session-persistence) |
 | `session/disposed` | `emit` | [`packages/core/session/src/index.ts:64`](../packages/core/session/src/index.ts) | [`session`](../packages/core/session) (`events.dispatch`) | - |
 | `session/event` | `emit` | [`packages/core/session/src/index.ts:83`](../packages/core/session/src/index.ts) | [`session`](../packages/core/session) (`events.dispatch`) | [`acp`](../packages/ui/acp), [`invariants`](../packages/support/invariants), [`jsonrpc`](../packages/ui/jsonrpc), [`session-persistence`](../packages/session-persistence/session-persistence), [`stdio-agent`](../packages/ui/stdio-agent) |
--- a/docs/persistence-catalog.md
+++ b/docs/persistence-catalog.md
@@ -64,7 +64,7 @@ Source: [`packages/core/session/src/types.ts:322`](../packages/core/session/src/
 Assembled assistant message for one step (derived history uses this). Carries the step's `usage` when the adapter reported token accounting, so the model output and its accounting travel together (there is no separate usage record). `usage` is absent when the adapter reported none.

 ```ts persistence-catalog
-'assistant/message': { turn: number; step: number; content: ContentBlock[]; usage?: TokenUsage }
+'assistant/message': { turn: number; step: number; content: ContentBlock[]; provenance: AssistantProvenance; usage?: TokenUsage }
 ```

 Types: [ContentBlock](core-data-structures/core.md) · [TokenUsage](core-data-structures/llm-streaming.md)
@@ -93,7 +93,7 @@ Marks the end of a compaction — log-only, releases the lock. `error` set if su
 'compact/end': { turn: number; error?: string }
 ```

-Source: [`packages/compact/compact/src/types.ts:46`](../packages/compact/compact/src/types.ts)
+Source: [`packages/compact/compact/src/types.ts:48`](../packages/compact/compact/src/types.ts)

 #### `compact/start` — log-only

@@ -110,7 +110,7 @@ Source: [`packages/compact/compact/src/types.ts:23`](../packages/compact/compact
 Provenance record of a completed summarization — log-only, no surfaceOp. The summary content is in `data.summary`; the actual surface replacement is performed by a subsequent `user/message` event that shadows the compacted range.

 ```ts persistence-catalog
-'compact/summary': { summary: ContentBlock[]; shadowedRange: { start: number; end: number }; shadowedSeqs: number[]; shadowedTokenCount: number; model: string; maxTokens?: number }
+'compact/summary': { summary: ContentBlock[]; shadowedRange: { start: number; end: number }; shadowedSeqs: number[]; shadowedTokenCount: number; provider: string; model: string; maxTokens?: number }
 ```

 Types: [ContentBlock](core-data-structures/core.md)
@@ -181,7 +181,7 @@ Source: [`packages/core/session/src/types.ts:374`](../packages/core/session/src/

 #### `request/header-delta` — log-only

-Amendment to the folded EpochHeader: at least one of a SystemDelta, a ToolsDelta, a whole replacement LlmCallConfig (four scalars — not worth diffing), or a whole replacement session prefix (`messagePrefix` — small advisory content, replaced whole; an EMPTY array encodes the transition to "none", mirroring the canonical form's absent field — the loop never produces one in practice: the prefix is composed once per instance and anchored by that instance's snapshot, so this arm exists for codec totality). Appended by the loop inside the step, before dispatch, when the header for this request differs from the fold of the log so far; the writer verifies `applyHeaderDelta(previous, delta)` reproduces the new header exactly and falls back to a `'fallback'` `request/header` snapshot when it cannot, so a logged delta ALWAYS round-trips. NOT a SurfaceEventType.
+Amendment to the folded EpochHeader: at least one of a SystemDelta, a ToolsDelta, a whole replacement LlmCallConfig (provider/model plus sampling scalars — not worth diffing), or a whole replacement session prefix (`messagePrefix` — small advisory content, replaced whole; an EMPTY array encodes the transition to "none", mirroring the canonical form's absent field — the loop never produces one in practice: the prefix is composed once per instance and anchored by that instance's snapshot, so this arm exists for codec totality). Appended by the loop inside the step, before dispatch, when the header for this request differs from the fold of the log so far; the writer verifies `applyHeaderDelta(previous, delta)` reproduces the new header exactly and falls back to a `'fallback'` `request/header` snapshot when it cannot, so a logged delta ALWAYS round-trips. NOT a SurfaceEventType.

 ```ts persistence-catalog
 'request/header-delta': { system?: SystemDelta; tools?: ToolsDelta; config?: LlmCallConfig; messagePrefix?: Message[] }
--- a/docs/rfc/INDEX.md
+++ b/docs/rfc/INDEX.md
@@ -141,6 +141,7 @@ Generated by `pnpm run gen-rfc-index` from the RFC tree — never edit by hand;
 | [The agent is a registration scope](implemented/architecture/2026-07-08-agent-scope-contexts.md) | 2026-07-08 |
 | [Single-file executable SDK runtime distribution (single-exe)](implemented/architecture/2026-07-10-single-file-executable-sdk-runtime-distribution.md) | 2026-07-10 |
 | [Agent-scope runtime design and correctness](implemented/architecture/2026-07-12-agent-scope-runtime-design.md) | 2026-07-12 |
+| [Provider-routed LLM adapters and a generic pi-ai backend](implemented/architecture/2026-07-14-provider-routed-llm-adapters.md) | 2026-07-14 |

 ### Process

--- a/docs/rfc/implemented/architecture/2026-07-14-provider-routed-llm-adapters.md
+++ b/docs/rfc/implemented/architecture/2026-07-14-provider-routed-llm-adapters.md
@@ -0,0 +1,89 @@
+# RFC: Provider-routed LLM adapters and a generic pi-ai backend
+
+Status: implemented
+
+## Problem
+
+`dsh-llm` registered adapters by exact model name. A plugin supplied a model list at Cordis startup, `LlmService` stored one adapter per listed string, and `GenerateOptions.model` selected the adapter and the provider model at once. This worked while both shipping adapters targeted the same two DeepSeek models, but it conflated two independent decisions: which upstream provider owns a request, and which model that provider should run.
+
+The conflation prevents a provider gateway from serving an open-ended model catalog. OpenRouter, for example, is one provider with many model ids, while a private OpenAI-compatible endpoint may add models without changing the Harness plugin tree. Every newly selected model currently needs to have been registered during plugin startup. The same model id can also exist at multiple providers, so model-only registration cannot state which provider the caller intended.
+
+`dsh-llm-pi-ai` exposed none of pi-ai's provider abstraction. It constructed an inline DeepSeek `openai-completions` model, applied DeepSeek-specific payload patches, and stamped every replayed assistant message as DeepSeek. pi-ai itself has a provider/model catalog, selects APIs such as `openai-responses`, `anthropic-messages`, and `google-generative-ai`, and preserves provider-specific response ids and reasoning/tool signatures for later turns. The Harness conversion dropped that provenance, so simply replacing the inline model with a catalog lookup would have made same-model replay and cross-provider handoff incomplete.
+
+The adapter configuration also assumes one DeepSeek API key and endpoint. A generic backend needs independent credentials and endpoint overrides per provider while leaving AWS, Google ADC, OAuth, and other ambient authentication mechanisms to pi-ai.
+
+## Decision
+
+### Provider is the adapter registration key
+
+`GenerateOptions` and `LlmCallConfig` carry `provider: string` beside `model: string`; `AgentOptions` carries the corresponding optional creation field. A loop request is valid only after both values are non-empty, and both values are part of the logged request header. `agent/request` may return a replacement pair on any step, so a session can switch providers and models without changing the Cordis plugin lifecycle.
+
+`LlmService` registers and resolves adapters by provider. `registerAdapter(providers, adapter)` checks the entire provider list before mutating the registry, rejects a duplicate with `DUPLICATE_ADAPTER`, and disposes the whole registration as one effect. `providers()` reports the registered keys. Model ids are not registered or enumerated by the service; the selected adapter validates or forwards them.
+
+A provider has exactly one adapter owner in a Cordis context. `dsh-llm-deepseek` registers `deepseek`; `dsh-llm-pi-ai` may also register `deepseek`, but loading both owners is a configuration error rather than an ordering rule or fallback. A deployment that wants the hand-rolled DeepSeek implementation excludes `deepseek` from the pi-ai profiles. A deployment that wants pi-ai's DeepSeek implementation does not mount `dsh-llm-deepseek`.
+
+`dsh-llm-deepseek` removes its model registration list and accepts any model string routed through provider `deepseek`. Its request serialization, `/chat/completions` endpoint, thinking options, SSE parsing, and error behavior remain unchanged; `options.model` is still sent verbatim.
+
+### Explicit pi-ai provider profiles
+
+`dsh-llm-pi-ai` takes one non-empty list of provider profiles. Provider names must be unique within the list and present in pi-ai's `getProviders()` result. Each profile contains the provider name plus optional `apiKey`, `baseURL`, headers, reasoning level and budgets, cache retention, transport, timeouts, and retry settings. Credentials are never global: an explicit key applies only to its profile, while an absent key lets pi-ai resolve its standard environment variable, OAuth token, AWS credential chain, Google ADC, or other provider-native ambient authentication. An explicitly empty key is invalid configuration rather than an environment fallback.
+
+The plugin registers all configured provider names against one `PiAiAdapter` in one all-or-nothing call. A request uses its provider to select the matching profile and finds its model in `getModels(provider)` to obtain the catalog descriptor. An unknown provider fails at plugin load; an unknown model fails before network I/O with `UNKNOWN_MODEL`. The catalog object is never mutated. When a profile supplies `baseURL`, the adapter clones the selected descriptor and overrides only `baseUrl`, so a private endpoint can retain pi-ai's API, capabilities, compatibility flags, context limits, and reasoning map. The private endpoint must implement the selected provider's protocol, and the model id must still exist in the installed pi-ai catalog.
+
+The adapter calls pi-ai's `streamSimple()` so each catalog model chooses its registered API implementation, including OpenAI Responses instead of Chat Completions where the descriptor says `openai-responses`. Harness temperature, maximum tokens, signal, session id, and the profile's common stream options flow through directly. Profile headers merge with the mandatory Harness attribution headers, with Harness attribution winning its reserved names. The adapter no longer maintains DeepSeek-specific payload rewrites or a provider-protocol matrix.
+
+pi-ai's common stream options do not expose stop sequences. `dsh-llm-pi-ai` rejects a defined Harness `stop` option with `UNSUPPORTED_OPTION` rather than silently ignoring it or growing a second provider-specific payload implementation. `dsh-llm-deepseek` continues to support `stop` through its native request serializer.
+
+### Durable assistant provenance and replay state
+
+Assistant messages carry provider-neutral provenance containing the request's `provider` and `model`, plus an optional JSON-serializable adapter replay state. A successful `assistant/message` session event records this provenance and `deriveMessages()` returns it with the assistant message. User, system, context, and tool-result messages carry no assistant provenance. The provider/model fields are authoritative loop data; an adapter owns only its opaque replay-state payload.
+
+A terminal successful `finish` chunk may carry replay state, and `BlockAssembler` retains it alongside usage and finish reason. The loop attaches it to the assistant provenance only when the post-`agent/step-result` content is structurally equal to the assembled provider output. A listener that rewrites content keeps the provider/model provenance but loses the now-stale replay state. Error and aborted responses do not produce a normal assistant message and therefore do not enter future model history.
+
+The pi-ai replay state is a versioned, minimal projection of its successful `AssistantMessage`: source API/provider/model, response id/model, stop reason, and index-aligned text, thinking, and tool-call signatures. It does not duplicate text or tool arguments already carried by Harness content blocks, and it omits diagnostics, timestamps, usage, and errors. On a later request, `LlmService` gives replay state to the target adapter only when the historical provider and target provider are currently owned by the same adapter instance. That adapter combines the logged Harness content with replay state when it can restore the historical response, and owns any required cross-model or cross-provider conversion. An adapter receiving replay state with an unknown version or mismatched block shape fails explicitly; a different adapter receives only provider-neutral content and provenance.
+
+This state is model-visible replay input and therefore follows the existing [reconstructable-request rule](../../implemented/architecture/2026-07-05-reconstructable-requests.md): it is present in both the terminal `finish` chunk and the assembled `assistant/message` provenance that drives derivation. Resume and fork preserve it verbatim. Compaction that shadows the assistant message also removes its replay state from the active surface; the summary is ordinary provider-neutral content.
+
+### Propagate the target through every request producer
+
+Every model-selection surface carries provider and model together: declarative agents, ACP and stdio app config, the JSON-RPC initialize request, subagent overrides and inheritance, workflow child overrides, and direct compaction summarization. Subagents inherit both fields from their parent before applying request overrides. The system-prompt variable set gains `provider` beside `model`.
+
+Compaction configuration gains `summarizationProvider` beside `summarizationModel`. Both are empty to inherit, or both are non-empty to select an explicit target; a half-configured pair fails load. Inheritance uses the last logged request target when one exists and falls back to the agent's creation options. `compact/summary` records both fields with the existing model-call envelope.
+
+The JSON-RPC runtime receives provider and model explicitly. Its convenience fallback mounts `dsh-llm-deepseek` only for provider `deepseek` when that provider has no registered owner; other missing providers fail without guessing an adapter.
+
+The on-disk session format remains the pre-release pinned version `0`, with no compatibility promise. Seed/load validation rejects request headers lacking provider and assistant messages lacking required provenance instead of accepting an old shape that can no longer reconstruct the request.
+
+## Alternatives considered
+
+**Keep model names as registry keys and add wildcard adapters.** A wildcard introduces fallback ordering between exact registrations and catch-all plugins, makes duplicate ownership dependent on listener order, and still cannot distinguish the same model id at two providers without another convention.
+
+**Encode provider and model into one string.** Values such as OpenRouter's `openai/gpt-*` already contain provider-like prefixes and slashes. A delimiter convention would leak routing syntax into every model selector and require escaping rules; two explicit fields are unambiguous and independently loggable.
+
+**Add `backend + provider + model`.** A backend key would allow `dsh-llm-deepseek` and pi-ai's DeepSeek implementation to coexist and switch per request. The accepted deployment rule is instead one adapter owner per provider: implementations of the same upstream are alternatives selected by plugin composition. A third routing dimension would burden every request and configuration for a capability with no current consumer.
+
+**Let `dsh-llm-pi-ai` automatically register every pi-ai provider.** This would claim ambient credentials and provider names the deployment never intended to expose, and would conflict with native adapters such as `dsh-llm-deepseek`. Explicit profiles make capability and credential scope reviewable.
+
+**Mount one pi-ai plugin instance per provider.** Separate instances isolate config but repeat plugin declarations and cannot make profile registration atomic. One adapter already receives provider on every request, so a validated profile map is the smaller lifecycle surface.
+
+**Accept arbitrary inline pi-ai model descriptors.** This would support catalog-external private model ids, but it exposes pi-ai's model and compatibility schema as Harness configuration and makes the adapter responsible for validating protocol-specific combinations. The first version supports custom endpoints by overriding `baseURL` on catalog models; custom descriptors require a separate decision after a real catalog-external deployment is identified.
+
+## Consequences
+
+- Provider names are deployment-wide route ownership keys: two providers may use the same model string, but mounting two adapters for one provider fails at load instead of creating fallback order.
+- Model selection no longer changes the Cordis plugin graph. Catalog-backed adapters can accept any installed catalog model selected after startup, while the native DeepSeek adapter forwards arbitrary DeepSeek model ids.
+- A custom `baseURL` preserves the selected catalog model's protocol and capabilities; it does not make catalog-external model ids valid. Private endpoints must implement that catalog entry's protocol.
+- pi-ai credentials and transport knobs are scoped per provider profile. An omitted key delegates to pi-ai ambient authentication, while an explicitly empty key is invalid.
+- `dsh-llm-pi-ai` rejects stop sequences because pi-ai's common stream API cannot express them; the native DeepSeek adapter retains its stop support.
+- Replay state is portable only within the adapter instance that owns both the historical and target providers. Cross-provider and cross-model restoration is an adapter responsibility, and another adapter receives provider-neutral history without the opaque state.
+- Current pre-release session JSONL requires provider/model request headers and assistant provenance. Older shapes remain version `0` but are rejected rather than migrated.
+
+## Testing
+
+- Unit coverage exercises registry conflicts, request reconstruction, session validation, profile resolution, option forwarding, native API selection including OpenAI Responses, conversion, replay validation, error mapping, cancellation, content rewrites, and same-instance versus different-instance replay dispatch.
+- Keyless loop/session tests and ACP snapshots exercise durable provider/model metadata, resume and fork propagation, workflow/subagent overrides, and unchanged user-visible transcripts; the key-gated DeepSeek e2e retains real provider streaming and tool follow-up coverage.
+- Public JSDoc, package READMEs, architecture and core-data-structure docs, generated catalogs, examples, session fixtures, and Python SDK pairs use provider/model targets consistently and are checked by the repository documentation and type-equivalence gates.
+
+## Risks
+
+This is a repo-wide pre-release API break: model-only request construction, adapter registration, app protocols, fixtures, and persisted version-0 event shapes all change together, with no compatibility aliases. The provider exclusivity rule deliberately prevents two implementations of the same upstream from coexisting in one context. A pi-ai dependency update can change the accepted provider/model catalog, so the lockfile and adapter e2e matrix define the tested set. Custom `baseURL` endpoints inherit the chosen catalog model's protocol assumptions and cannot repair an incompatible proxy. Catalog-external model descriptors and multimodal content remain unsupported. pi-ai replay state may contain opaque encrypted reasoning signatures; it is persisted because the provider requires it for continuity, but it is never rendered or logged outside the existing session record.
--- a/docs/tool-catalog.md
+++ b/docs/tool-catalog.md
@@ -477,10 +477,10 @@ todo_write is session-owned state; UIs render the latest todo/write event as a c

 Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn.

-The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result.
+The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, provider?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result.

 Script-body hooks:
- `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `model` (override). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly.
+- `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `provider` and `model` (paired LLM target overrides). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly.
 - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages.
 - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`.
 - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim.
@@ -527,6 +527,10 @@ Constraints: concurrency and total-agent caps apply; no filesystem, network, tim
                "type": "string",
                "description": "Optional one-line description of the phase."
              },
+              "provider": {
+                "type": "string",
+                "description": "Optional provider override this phase is expected to use."
+              },
              "model": {
                "type": "string",
                "description": "Optional model override this phase is expected to use."
--- a/examples/acp-agent/advanced.cordis.snapshot.yml
+++ b/examples/acp-agent/advanced.cordis.snapshot.yml
@@ -12,6 +12,7 @@
      - id: acp-agent
        name: '@deepseek-ai/dsh-acp-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
          tools:
--- a/examples/acp-agent/advanced.cordis.yml
+++ b/examples/acp-agent/advanced.cordis.yml
@@ -10,6 +10,7 @@
      - id: acp-agent
        name: '@deepseek-ai/dsh-acp-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
          tools:
--- a/examples/acp-agent/both-mode.cordis.snapshot.yml
+++ b/examples/acp-agent/both-mode.cordis.snapshot.yml
@@ -15,6 +15,7 @@
      - id: acp-agent
        name: '@deepseek-ai/dsh-acp-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
          tools:
--- a/examples/acp-agent/both-mode.cordis.yml
+++ b/examples/acp-agent/both-mode.cordis.yml
@@ -14,6 +14,7 @@
      - id: acp-agent
        name: '@deepseek-ai/dsh-acp-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
          tools:
--- a/examples/acp-agent/code-mode.cordis.snapshot.yml
+++ b/examples/acp-agent/code-mode.cordis.snapshot.yml
@@ -15,6 +15,7 @@
      - id: acp-agent
        name: '@deepseek-ai/dsh-acp-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
          tools:
--- a/examples/acp-agent/code-mode.cordis.yml
+++ b/examples/acp-agent/code-mode.cordis.yml
@@ -15,6 +15,7 @@
      - id: acp-agent
        name: '@deepseek-ai/dsh-acp-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
          tools:
--- a/examples/acp-agent/cordis.yml
+++ b/examples/acp-agent/cordis.yml
@@ -19,9 +19,6 @@
  config:
    apiKey: !!js process.env.DEEPSEEK_API_KEY
    baseURL: !!js process.env.DEEPSEEK_BASE_URL
-    models:
-      - deepseek-v4-flash
-      - deepseek-v4-pro

 # Local bash executor for agent-core's tool-bash schema (one of several tool
 # stacks in this tree: filesystem, subagent, and todo_write load below).
@@ -36,6 +33,7 @@
 - id: acp-agent
  name: '@deepseek-ai/dsh-acp-agent'
  config:
+    provider: deepseek
    model: deepseek-v4-flash
    persistenceRoot: !!js process.env.DSH_SNAPSHOT_SESSIONS_ROOT ?? './.sessions'
    # The persona: identity + behavior only, nothing about transports or
--- a/examples/acp-agent/tests/snapshots/advanced-toolchain/session.1.jsonl
+++ b/examples/acp-agent/tests/snapshots/advanced-toolchain/session.1.jsonl
--- a/examples/acp-agent/tests/snapshots/advanced-toolchain/session.2.jsonl
+++ b/examples/acp-agent/tests/snapshots/advanced-toolchain/session.2.jsonl
--- a/examples/acp-agent/tests/snapshots/advanced-toolchain/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/advanced-toolchain/session.jsonl
--- a/examples/acp-agent/tests/snapshots/advanced-toolchain/system-prompt.golden.md
+++ b/examples/acp-agent/tests/snapshots/advanced-toolchain/system-prompt.golden.md
@@ -115,7 +115,7 @@ declare const tools: {
      status: "pending" | "in_progress" | "completed";
    })[];
  }): Promise<string>;
-  /** Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn. The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result. Script-body hooks: - `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `model` (override). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly. - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages. - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`. - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim. Misused hooks (bad arguments, unknown options, unsupported schemas, tripped caps) throw errors that ALWAYS kill the script — they never dissolve into a per-item `null`. Constraints: concurrency and total-agent caps apply; no filesystem, network, timers, or Node.js APIs are provided — the agents do the work, the script only coordinates them. The run executes in the foreground: this call returns when the whole script finishes. */
+  /** Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn. The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, provider?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result. Script-body hooks: - `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `provider` and `model` (paired LLM target overrides). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly. - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages. - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`. - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim. Misused hooks (bad arguments, unknown options, unsupported schemas, tripped caps) throw errors that ALWAYS kill the script — they never dissolve into a per-item `null`. Constraints: concurrency and total-agent caps apply; no filesystem, network, timers, or Node.js APIs are provided — the agents do the work, the script only coordinates them. The run executes in the foreground: this call returns when the whole script finishes. */
  workflow(args: {
    /** The plain-JS workflow script body (top-level await allowed; NO `export const meta` statement; end with `return <json-value>`). */
    script: string;
@@ -133,6 +133,8 @@ declare const tools: {
        title: string;
        /** Optional one-line description of the phase. */
        detail?: string;
+        /** Optional provider override this phase is expected to use. */
+        provider?: string;
        /** Optional model override this phase is expected to use. */
        model?: string;
      }[];
--- a/examples/acp-agent/tests/snapshots/both-mode-turn/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/both-mode-turn/session.jsonl
--- a/examples/acp-agent/tests/snapshots/both-mode-turn/system-prompt.golden.md
+++ b/examples/acp-agent/tests/snapshots/both-mode-turn/system-prompt.golden.md
@@ -100,7 +100,7 @@ declare const tools: {
      status: "pending" | "in_progress" | "completed";
    })[];
  }): Promise<string>;
-  /** Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn. The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result. Script-body hooks: - `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `model` (override). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly. - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages. - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`. - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim. Misused hooks (bad arguments, unknown options, unsupported schemas, tripped caps) throw errors that ALWAYS kill the script — they never dissolve into a per-item `null`. Constraints: concurrency and total-agent caps apply; no filesystem, network, timers, or Node.js APIs are provided — the agents do the work, the script only coordinates them. The run executes in the foreground: this call returns when the whole script finishes. */
+  /** Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn. The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, provider?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result. Script-body hooks: - `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `provider` and `model` (paired LLM target overrides). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly. - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages. - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`. - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim. Misused hooks (bad arguments, unknown options, unsupported schemas, tripped caps) throw errors that ALWAYS kill the script — they never dissolve into a per-item `null`. Constraints: concurrency and total-agent caps apply; no filesystem, network, timers, or Node.js APIs are provided — the agents do the work, the script only coordinates them. The run executes in the foreground: this call returns when the whole script finishes. */
  workflow(args: {
    /** The plain-JS workflow script body (top-level await allowed; NO `export const meta` statement; end with `return <json-value>`). */
    script: string;
@@ -118,6 +118,8 @@ declare const tools: {
        title: string;
        /** Optional one-line description of the phase. */
        detail?: string;
+        /** Optional provider override this phase is expected to use. */
+        provider?: string;
        /** Optional model override this phase is expected to use. */
        model?: string;
      }[];
--- a/examples/acp-agent/tests/snapshots/cancel/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/cancel/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":0,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":0,"data":{"content":[{"type":"text","text":"Start a long task; this turn will be cancelled mid-stream."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":0,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":0,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":0,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":0,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"text"}}}
 {"type":"assistant/chunk","seq":5,"time":0,"data":{"turn":1,"step":1,"chunk":{"type":"text-delta","index":0,"text":"partial"}}}
 {"type":"step/end","seq":6,"time":0,"data":{"turn":1,"step":1}}
--- a/examples/acp-agent/tests/snapshots/code-mode-turn/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/code-mode-turn/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783611771394,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783611771394,"data":{"content":[{"type":"text","text":"Using ONE run_code program: call the bash tool twice — exactly `echo CODE_ONE` then exactly `echo CODE_TWO` — and return the two outputs joined with a plus sign. Then reply with that joined string only and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783611771396,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783611771396,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":[{"name":"run_code","description":"Execute a TypeScript program against the available tools. Write the BODY of an async function (erasable syntax only; top-level `await` and `return` work) and call tools as `await tools.name(args)` per the declarations in the system prompt. Only what you print or return comes back — curate it.","parameters":{"type":"object","properties":{"code":{"type":"string","description":"The program: the body of an async TypeScript function."}},"required":["code"]}}]},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783611771396,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":[{"name":"run_code","description":"Execute a TypeScript program against the available tools. Write the BODY of an async function (erasable syntax only; top-level `await` and `return` work) and call tools as `await tools.name(args)` per the declarations in the system prompt. Only what you print or return comes back — curate it.","parameters":{"type":"object","properties":{"code":{"type":"string","description":"The program: the body of an async TypeScript function."}},"required":["code"]}}]},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783611771869,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783611771869,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783611771978,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -108,7 +108,7 @@
 {"type":"assistant/chunk","seq":106,"time":1783611772836,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_DRxnM6R1TThfDwcudW0f2050","name":"run_code","arguments":"{\"code\": \"const out1 = await tools.bash({ command: \\\"echo CODE_ONE\\\", description: \\\"First echo\\\" });\\nconst out2 = await tools.bash({ command: \\\"echo CODE_TWO\\\", description: \\\"Second echo\\\" });\\nreturn out1.trim() + \\\"+\\\" + out2.trim();\"}"}}}}
 {"type":"assistant/chunk","seq":107,"time":1783611772836,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":3009,"outputTokens":133,"cacheReadTokens":0,"reasoningTokens":29}}}}
 {"type":"assistant/chunk","seq":108,"time":1783611772836,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":109,"time":1783611772840,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants a single run_code program that calls bash twice, then returns the two outputs joined with a plus sign. Let me write this."},{"type":"tool-call","id":"call_00_DRxnM6R1TThfDwcudW0f2050","name":"run_code","arguments":"{\"code\": \"const out1 = await tools.bash({ command: \\\"echo CODE_ONE\\\", description: \\\"First echo\\\" });\\nconst out2 = await tools.bash({ command: \\\"echo CODE_TWO\\\", description: \\\"Second echo\\\" });\\nreturn out1.trim() + \\\"+\\\" + out2.trim();\"}"}],"usage":{"inputTokens":3009,"outputTokens":133,"cacheReadTokens":0,"reasoningTokens":29}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108],"surfaceOp":"append"}
+{"type":"assistant/message","seq":109,"time":1783611772840,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants a single run_code program that calls bash twice, then returns the two outputs joined with a plus sign. Let me write this."},{"type":"tool-call","id":"call_00_DRxnM6R1TThfDwcudW0f2050","name":"run_code","arguments":"{\"code\": \"const out1 = await tools.bash({ command: \\\"echo CODE_ONE\\\", description: \\\"First echo\\\" });\\nconst out2 = await tools.bash({ command: \\\"echo CODE_TWO\\\", description: \\\"Second echo\\\" });\\nreturn out1.trim() + \\\"+\\\" + out2.trim();\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":3009,"outputTokens":133,"cacheReadTokens":0,"reasoningTokens":29}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108],"surfaceOp":"append"}
 {"type":"tool/call","seq":110,"time":1783611772840,"data":{"turn":1,"step":1,"callId":"call_00_DRxnM6R1TThfDwcudW0f2050","name":"run_code","arguments":"{\"code\": \"const out1 = await tools.bash({ command: \\\"echo CODE_ONE\\\", description: \\\"First echo\\\" });\\nconst out2 = await tools.bash({ command: \\\"echo CODE_TWO\\\", description: \\\"Second echo\\\" });\\nreturn out1.trim() + \\\"+\\\" + out2.trim();\"}"}}
 {"type":"tool/code-dispatch","seq":111,"time":1783611772933,"data":{"parentCallId":"call_00_DRxnM6R1TThfDwcudW0f2050","subCallId":"call_00_DRxnM6R1TThfDwcudW0f2050:code:1","name":"bash","arguments":{"command":"echo CODE_ONE","description":"First echo"},"isError":false,"resultSummary":"CODE_ONE\n"}}
 {"type":"tool/code-dispatch","seq":112,"time":1783611772936,"data":{"parentCallId":"call_00_DRxnM6R1TThfDwcudW0f2050","subCallId":"call_00_DRxnM6R1TThfDwcudW0f2050:code:2","name":"bash","arguments":{"command":"echo CODE_TWO","description":"Second echo"},"isError":false,"resultSummary":"CODE_TWO\n"}}
@@ -145,6 +145,6 @@
 {"type":"assistant/chunk","seq":143,"time":1783611773686,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"CODE_ONE+CODE_TWO"}}}}
 {"type":"assistant/chunk","seq":144,"time":1783611773686,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":89,"outputTokens":25,"cacheReadTokens":3072,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":145,"time":1783611773686,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":146,"time":1783611773687,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The output is exactly what the user asked for: CODE_ONE+CODE_TWO"},{"type":"text","text":"CODE_ONE+CODE_TWO"}],"usage":{"inputTokens":89,"outputTokens":25,"cacheReadTokens":3072,"reasoningTokens":17}},"sourceEventSeqs":[116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145],"surfaceOp":"append"}
+{"type":"assistant/message","seq":146,"time":1783611773687,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The output is exactly what the user asked for: CODE_ONE+CODE_TWO"},{"type":"text","text":"CODE_ONE+CODE_TWO"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":89,"outputTokens":25,"cacheReadTokens":3072,"reasoningTokens":17}},"sourceEventSeqs":[116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145],"surfaceOp":"append"}
 {"type":"step/end","seq":147,"time":1783611773687,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":148,"time":1783611773687,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/code-mode-turn/system-prompt.golden.md
+++ b/examples/acp-agent/tests/snapshots/code-mode-turn/system-prompt.golden.md
@@ -100,7 +100,7 @@ declare const tools: {
      status: "pending" | "in_progress" | "completed";
    })[];
  }): Promise<string>;
-  /** Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn. The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result. Script-body hooks: - `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `model` (override). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly. - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages. - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`. - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim. Misused hooks (bad arguments, unknown options, unsupported schemas, tripped caps) throw errors that ALWAYS kill the script — they never dissolve into a per-item `null`. Constraints: concurrency and total-agent caps apply; no filesystem, network, timers, or Node.js APIs are provided — the agents do the work, the script only coordinates them. The run executes in the foreground: this call returns when the whole script finishes. */
+  /** Run a JavaScript workflow script that orchestrates subagents at scale. Use this for work that fans out across many independent pieces — an audit over many files, a migration, multi-angle research, adversarial verification of findings — where you write the orchestration as a script instead of delegating turn by turn. The workflow's identity rides the `meta` parameter as JSON: required `name` (short kebab-case) and `description` strings, optional `whenToUse` string and `phases` array (`{title, detail?, provider?, model?}`). The `script` parameter is the plain JavaScript body ONLY (NOT TypeScript, and NO `export const meta` statement — meta is a parameter, not code), running with top-level await; end with `return <value>` — the value must be JSON-serializable and is this tool's result. Script-body hooks: - `agent(prompt, opts?): Promise<any>` — run one subagent to completion. Without `opts.schema` it resolves to the child's final text; with `opts.schema` (an object-rooted JSON Schema using ONLY type/properties/required/additionalProperties/items/enum/const — no oneOf/pattern/format/numeric bounds) it resolves to the validated object. Resolves `null` when the child fails (filter with `.filter(Boolean)`). Other opts: `label` (display), `phase` (progress group), `provider` and `model` (paired LLM target overrides). Anything else (`effort`/`isolation`/`agentType`) is rejected loudly. - `pipeline(items, ...stages): Promise<any[]>` — run each item through the stages independently with NO barrier between stages (prefer this for multi-stage work). Each stage receives `(prev, item, index)`. An ordinary stage throw drops that ITEM to `null` and skips its remaining stages. - `parallel(thunks): Promise<any[]>` — run zero-argument functions concurrently and await ALL of them (a barrier; use only when a stage genuinely needs every prior result together). A throwing thunk resolves to `null`. - `phase(title)` — start a progress phase; `log(message)` — narrate progress; `args` — the tool call's `args` input, verbatim. Misused hooks (bad arguments, unknown options, unsupported schemas, tripped caps) throw errors that ALWAYS kill the script — they never dissolve into a per-item `null`. Constraints: concurrency and total-agent caps apply; no filesystem, network, timers, or Node.js APIs are provided — the agents do the work, the script only coordinates them. The run executes in the foreground: this call returns when the whole script finishes. */
  workflow(args: {
    /** The plain-JS workflow script body (top-level await allowed; NO `export const meta` statement; end with `return <json-value>`). */
    script: string;
@@ -118,6 +118,8 @@ declare const tools: {
        title: string;
        /** Optional one-line description of the phase. */
        detail?: string;
+        /** Optional provider override this phase is expected to use. */
+        provider?: string;
        /** Optional model override this phase is expected to use. */
        model?: string;
      }[];
--- a/examples/acp-agent/tests/snapshots/error-finish/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/error-finish/session.jsonl
@@ -2,6 +2,6 @@
 {"type":"turn/start","seq":0,"time":0,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":0,"data":{"content":[{"type":"text","text":"This prompt triggers a recorded provider error."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":0,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":0,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":0,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"step/end","seq":4,"time":0,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":5,"time":0,"data":{"turn":1,"reason":{"kind":"error","step":1,"message":"simulated provider error (HTTP 401)","code":"AUTH"}}}
--- a/examples/acp-agent/tests/snapshots/fs-edit/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-edit/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352084740,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352084740,"data":{"content":[{"type":"text","text":"First use the read tool to read config.txt in the current directory. Then use the edit tool (NOT bash) to replace the literal text DEBUG with RELEASE in that file. Then reply with exactly the single word DONE."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352084742,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352084742,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352084742,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352085426,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352085426,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352085563,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -67,7 +67,7 @@
 {"type":"assistant/chunk","seq":65,"time":1783352086057,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_S6krdIDHoSCGWv7WnXX97617","name":"read","arguments":"{\"file_path\": \"config.txt\"}"}}}}
 {"type":"assistant/chunk","seq":66,"time":1783352086057,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2900,"outputTokens":91,"cacheReadTokens":0,"reasoningTokens":46}}}}
 {"type":"assistant/chunk","seq":67,"time":1783352086057,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":68,"time":1783352086059,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Read config.txt in the current directory\n2. Use the edit tool to replace DEBUG with RELEASE\n3. Reply with exactly \"DONE\"\n\nLet me start by reading the file."},{"type":"tool-call","id":"call_00_S6krdIDHoSCGWv7WnXX97617","name":"read","arguments":"{\"file_path\": \"config.txt\"}"}],"usage":{"inputTokens":2900,"outputTokens":91,"cacheReadTokens":0,"reasoningTokens":46}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67],"surfaceOp":"append"}
+{"type":"assistant/message","seq":68,"time":1783352086059,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Read config.txt in the current directory\n2. Use the edit tool to replace DEBUG with RELEASE\n3. Reply with exactly \"DONE\"\n\nLet me start by reading the file."},{"type":"tool-call","id":"call_00_S6krdIDHoSCGWv7WnXX97617","name":"read","arguments":"{\"file_path\": \"config.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2900,"outputTokens":91,"cacheReadTokens":0,"reasoningTokens":46}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67],"surfaceOp":"append"}
 {"type":"tool/call","seq":69,"time":1783352086059,"data":{"turn":1,"step":1,"callId":"call_00_S6krdIDHoSCGWv7WnXX97617","name":"read","arguments":"{\"file_path\": \"config.txt\"}"}}
 {"type":"tool/result","seq":70,"time":1783352086065,"data":{"turn":1,"step":1,"callId":"call_00_S6krdIDHoSCGWv7WnXX97617","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-0BxHdV/config.txt</path>\n<type>file</type>\n<content>\n1: mode=DEBUG\n2: level=info\n\n(End of file - total 2 lines)\n</content>"}],"isError":false},"sourceEventSeqs":[69],"surfaceOp":"append"}
 {"type":"step/end","seq":71,"time":1783352086065,"data":{"turn":1,"step":1}}
@@ -127,7 +127,7 @@
 {"type":"assistant/chunk","seq":125,"time":1783352087469,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_vOytneZ0XpsLslEEJAxR6398","name":"edit","arguments":"{\"file_path\": \"config.txt\", \"old_string\": \"DEBUG\", \"new_string\": \"RELEASE\"}"}}}}
 {"type":"assistant/chunk","seq":126,"time":1783352087469,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":241,"outputTokens":98,"cacheReadTokens":2816,"reasoningTokens":18}}}}
 {"type":"assistant/chunk","seq":127,"time":1783352087469,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":128,"time":1783352087469,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"Now I need to replace \"DEBUG\" with \"RELEASE\" using the edit tool."},{"type":"tool-call","id":"call_00_vOytneZ0XpsLslEEJAxR6398","name":"edit","arguments":"{\"file_path\": \"config.txt\", \"old_string\": \"DEBUG\", \"new_string\": \"RELEASE\"}"}],"usage":{"inputTokens":241,"outputTokens":98,"cacheReadTokens":2816,"reasoningTokens":18}},"sourceEventSeqs":[73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127],"surfaceOp":"append"}
+{"type":"assistant/message","seq":128,"time":1783352087469,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"Now I need to replace \"DEBUG\" with \"RELEASE\" using the edit tool."},{"type":"tool-call","id":"call_00_vOytneZ0XpsLslEEJAxR6398","name":"edit","arguments":"{\"file_path\": \"config.txt\", \"old_string\": \"DEBUG\", \"new_string\": \"RELEASE\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":241,"outputTokens":98,"cacheReadTokens":2816,"reasoningTokens":18}},"sourceEventSeqs":[73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127],"surfaceOp":"append"}
 {"type":"tool/call","seq":129,"time":1783352087469,"data":{"turn":1,"step":2,"callId":"call_00_vOytneZ0XpsLslEEJAxR6398","name":"edit","arguments":"{\"file_path\": \"config.txt\", \"old_string\": \"DEBUG\", \"new_string\": \"RELEASE\"}"}}
 {"type":"tool/result","seq":130,"time":1783352087476,"data":{"turn":1,"step":2,"callId":"call_00_vOytneZ0XpsLslEEJAxR6398","content":[{"type":"text","text":"The file /tmp/acp-snap-cwd-0BxHdV/config.txt has been updated successfully."}],"isError":false,"meta":{"diffs":[{"path":"config.txt","oldText":"mode=DEBUG\nlevel=info","newText":"mode=RELEASE\nlevel=info"}]}},"sourceEventSeqs":[129],"surfaceOp":"append"}
 {"type":"step/end","seq":131,"time":1783352087477,"data":{"turn":1,"step":2}}
@@ -154,6 +154,6 @@
 {"type":"assistant/chunk","seq":152,"time":1783352088523,"data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":153,"time":1783352088523,"data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":244,"outputTokens":17,"cacheReadTokens":2944,"reasoningTokens":14}}}}
 {"type":"assistant/chunk","seq":154,"time":1783352088523,"data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":155,"time":1783352088523,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"Done. The user wants me to reply with exactly \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":244,"outputTokens":17,"cacheReadTokens":2944,"reasoningTokens":14}},"sourceEventSeqs":[133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154],"surfaceOp":"append"}
+{"type":"assistant/message","seq":155,"time":1783352088523,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"Done. The user wants me to reply with exactly \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":244,"outputTokens":17,"cacheReadTokens":2944,"reasoningTokens":14}},"sourceEventSeqs":[133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154],"surfaceOp":"append"}
 {"type":"step/end","seq":156,"time":1783352088523,"data":{"turn":1,"step":3}}
 {"type":"turn/end","seq":157,"time":1783352088524,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/fs-policy-reject/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-policy-reject/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783611702550,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783611702550,"data":{"content":[{"type":"text","text":"Do NOT use the read tool and do NOT use bash or shell commands. Immediately use the edit tool to replace the literal text blue with green in settings.txt in the current directory. Do not read the file first. After the tool result, reply with exactly the single word DONE."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783611702550,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783611702551,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783611702551,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783611703185,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783611703185,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783611703352,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -75,7 +75,7 @@
 {"type":"assistant/chunk","seq":73,"time":1783611703969,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_x0zlnXl5JOxLrAYL9y7P0119","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}}}}
 {"type":"assistant/chunk","seq":74,"time":1783611703969,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":3132,"outputTokens":115,"cacheReadTokens":0,"reasoningTokens":36}}}}
 {"type":"assistant/chunk","seq":75,"time":1783611703969,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":76,"time":1783611703972,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the edit tool to replace \"blue\" with \"green\" in settings.txt without reading the file first, and then reply with just \"DONE\"."},{"type":"tool-call","id":"call_00_x0zlnXl5JOxLrAYL9y7P0119","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}],"usage":{"inputTokens":3132,"outputTokens":115,"cacheReadTokens":0,"reasoningTokens":36}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75],"surfaceOp":"append"}
+{"type":"assistant/message","seq":76,"time":1783611703972,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the edit tool to replace \"blue\" with \"green\" in settings.txt without reading the file first, and then reply with just \"DONE\"."},{"type":"tool-call","id":"call_00_x0zlnXl5JOxLrAYL9y7P0119","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":3132,"outputTokens":115,"cacheReadTokens":0,"reasoningTokens":36}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75],"surfaceOp":"append"}
 {"type":"tool/call","seq":77,"time":1783611703972,"data":{"turn":1,"step":1,"callId":"call_00_x0zlnXl5JOxLrAYL9y7P0119","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}}
 {"type":"tool/result","seq":78,"time":1783611703978,"data":{"turn":1,"step":1,"callId":"call_00_x0zlnXl5JOxLrAYL9y7P0119","content":[{"type":"text","text":"Error: edit requires reading \"/var/folders/2c/psb0_fmx7hbgz558xjt_f0l00000gn/T/acp-snap-cwd-QzoqnB/settings.txt\" first"}],"isError":true,"error":{"name":"FsError","code":"FS_NOT_OBSERVED"}},"sourceEventSeqs":[77],"surfaceOp":"append"}
 {"type":"step/end","seq":79,"time":1783611703978,"data":{"turn":1,"step":1}}
@@ -142,7 +142,7 @@
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 {"type":"assistant/chunk","seq":141,"time":1783611705572,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":235,"outputTokens":89,"cacheReadTokens":3072,"reasoningTokens":44}}}}
 {"type":"assistant/chunk","seq":142,"time":1783611705572,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":143,"time":1783611705573,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The edit tool requires reading the file first. The user said \"Do not read the file first\" but the tool's own constraints require reading. I need to follow the tool requirements. Let me read the file first."},{"type":"tool-call","id":"call_00_tfr0gdIclW92oIEgi7NF0891","name":"read","arguments":"{\"file_path\": \"settings.txt\"}"}],"usage":{"inputTokens":235,"outputTokens":89,"cacheReadTokens":3072,"reasoningTokens":44}},"sourceEventSeqs":[81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142],"surfaceOp":"append"}
+{"type":"assistant/message","seq":143,"time":1783611705573,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The edit tool requires reading the file first. The user said \"Do not read the file first\" but the tool's own constraints require reading. I need to follow the tool requirements. Let me read the file first."},{"type":"tool-call","id":"call_00_tfr0gdIclW92oIEgi7NF0891","name":"read","arguments":"{\"file_path\": \"settings.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":235,"outputTokens":89,"cacheReadTokens":3072,"reasoningTokens":44}},"sourceEventSeqs":[81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142],"surfaceOp":"append"}
 {"type":"tool/call","seq":144,"time":1783611705573,"data":{"turn":1,"step":2,"callId":"call_00_tfr0gdIclW92oIEgi7NF0891","name":"read","arguments":"{\"file_path\": \"settings.txt\"}"}}
 {"type":"tool/result","seq":145,"time":1783611705579,"data":{"turn":1,"step":2,"callId":"call_00_tfr0gdIclW92oIEgi7NF0891","content":[{"type":"text","text":"<path>/var/folders/2c/psb0_fmx7hbgz558xjt_f0l00000gn/T/acp-snap-cwd-QzoqnB/settings.txt</path>\n<type>file</type>\n<content>\n1: color: blue\n\n(End of file - total 1 lines)\n</content>"}],"isError":false},"sourceEventSeqs":[144],"surfaceOp":"append"}
 {"type":"step/end","seq":146,"time":1783611705579,"data":{"turn":1,"step":2}}
@@ -223,7 +223,7 @@
 {"type":"assistant/chunk","seq":221,"time":1783611707096,"data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_GVknJu2tksKkP4lALCwh0926","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}}}}
 {"type":"assistant/chunk","seq":222,"time":1783611707096,"data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":281,"outputTokens":119,"cacheReadTokens":3200,"reasoningTokens":40}}}}
 {"type":"assistant/chunk","seq":223,"time":1783611707096,"data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":224,"time":1783611707097,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"The file contains \"color: blue\". I need to replace \"blue\" with \"green\". The edit tool said it requires reading first — now I've read it, so the edit should work."},{"type":"tool-call","id":"call_00_GVknJu2tksKkP4lALCwh0926","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}],"usage":{"inputTokens":281,"outputTokens":119,"cacheReadTokens":3200,"reasoningTokens":40}},"sourceEventSeqs":[148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223],"surfaceOp":"append"}
+{"type":"assistant/message","seq":224,"time":1783611707097,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"The file contains \"color: blue\". I need to replace \"blue\" with \"green\". The edit tool said it requires reading first — now I've read it, so the edit should work."},{"type":"tool-call","id":"call_00_GVknJu2tksKkP4lALCwh0926","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":281,"outputTokens":119,"cacheReadTokens":3200,"reasoningTokens":40}},"sourceEventSeqs":[148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223],"surfaceOp":"append"}
 {"type":"tool/call","seq":225,"time":1783611707097,"data":{"turn":1,"step":3,"callId":"call_00_GVknJu2tksKkP4lALCwh0926","name":"edit","arguments":"{\"file_path\": \"settings.txt\", \"old_string\": \"blue\", \"new_string\": \"green\"}"}}
 {"type":"tool/result","seq":226,"time":1783611707114,"data":{"turn":1,"step":3,"callId":"call_00_GVknJu2tksKkP4lALCwh0926","content":[{"type":"text","text":"The file /var/folders/2c/psb0_fmx7hbgz558xjt_f0l00000gn/T/acp-snap-cwd-QzoqnB/settings.txt has been updated successfully."}],"isError":false,"meta":{"diffs":[{"path":"settings.txt","oldText":"color: blue","newText":"color: green"}]}},"sourceEventSeqs":[225],"surfaceOp":"append"}
 {"type":"step/end","seq":227,"time":1783611707114,"data":{"turn":1,"step":3}}
@@ -253,6 +253,6 @@
 {"type":"assistant/chunk","seq":251,"time":1783611707952,"data":{"turn":1,"step":4,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":252,"time":1783611707952,"data":{"turn":1,"step":4,"chunk":{"type":"usage","usage":{"inputTokens":202,"outputTokens":20,"cacheReadTokens":3456,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":253,"time":1783611707952,"data":{"turn":1,"step":4,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":254,"time":1783611707953,"data":{"turn":1,"step":4,"content":[{"type":"reasoning","text":"The replacement was successful. I'll reply with just \"DONE\" as instructed."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":202,"outputTokens":20,"cacheReadTokens":3456,"reasoningTokens":17}},"sourceEventSeqs":[229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253],"surfaceOp":"append"}
+{"type":"assistant/message","seq":254,"time":1783611707953,"data":{"turn":1,"step":4,"content":[{"type":"reasoning","text":"The replacement was successful. I'll reply with just \"DONE\" as instructed."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":202,"outputTokens":20,"cacheReadTokens":3456,"reasoningTokens":17}},"sourceEventSeqs":[229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253],"surfaceOp":"append"}
 {"type":"step/end","seq":255,"time":1783611707953,"data":{"turn":1,"step":4}}
 {"type":"turn/end","seq":256,"time":1783611707953,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/fs-read-window/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-read-window/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352099838,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352099839,"data":{"content":[{"type":"text","text":"Use the read tool (NOT bash) with offset 5 and limit 4 to read lines 5 through 8 of big.txt in the current directory. Then reply with exactly the single word DONE."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352099840,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352099841,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352099841,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352100468,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352100468,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352100587,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -89,7 +89,7 @@
 {"type":"assistant/chunk","seq":87,"time":1783352101346,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_GIZwZS9a7vhWTFCIc7Z35497","name":"read","arguments":"{\"file_path\": \"big.txt\", \"offset\": 5, \"limit\": 4}"}}}}
 {"type":"assistant/chunk","seq":88,"time":1783352101346,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2894,"outputTokens":133,"cacheReadTokens":0,"reasoningTokens":56}}}}
 {"type":"assistant/chunk","seq":89,"time":1783352101346,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":90,"time":1783352101348,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the read tool with offset 5 and limit 4 to read lines 5 through 8 of big.txt in the current directory. Then reply with exactly the single word DONE.\n\nLet me first check the current directory, then read the file."},{"type":"tool-call","id":"call_00_GIZwZS9a7vhWTFCIc7Z35497","name":"read","arguments":"{\"file_path\": \"big.txt\", \"offset\": 5, \"limit\": 4}"}],"usage":{"inputTokens":2894,"outputTokens":133,"cacheReadTokens":0,"reasoningTokens":56}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89],"surfaceOp":"append"}
+{"type":"assistant/message","seq":90,"time":1783352101348,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the read tool with offset 5 and limit 4 to read lines 5 through 8 of big.txt in the current directory. Then reply with exactly the single word DONE.\n\nLet me first check the current directory, then read the file."},{"type":"tool-call","id":"call_00_GIZwZS9a7vhWTFCIc7Z35497","name":"read","arguments":"{\"file_path\": \"big.txt\", \"offset\": 5, \"limit\": 4}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2894,"outputTokens":133,"cacheReadTokens":0,"reasoningTokens":56}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89],"surfaceOp":"append"}
 {"type":"tool/call","seq":91,"time":1783352101348,"data":{"turn":1,"step":1,"callId":"call_00_GIZwZS9a7vhWTFCIc7Z35497","name":"read","arguments":"{\"file_path\": \"big.txt\", \"offset\": 5, \"limit\": 4}"}}
 {"type":"tool/result","seq":92,"time":1783352101353,"data":{"turn":1,"step":1,"callId":"call_00_GIZwZS9a7vhWTFCIc7Z35497","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-N9HCkt/big.txt</path>\n<type>file</type>\n<content>\n5: line five\n6: line six\n7: line seven\n8: line eight\n\n(Showing lines 5-8 of 10. Use offset=9 to continue.)\n</content>"}],"isError":false},"sourceEventSeqs":[91],"surfaceOp":"append"}
 {"type":"step/end","seq":93,"time":1783352101353,"data":{"turn":1,"step":1}}
@@ -129,6 +129,6 @@
 {"type":"assistant/chunk","seq":127,"time":1783352102357,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":128,"time":1783352102358,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":292,"outputTokens":30,"cacheReadTokens":2816,"reasoningTokens":27}}}}
 {"type":"assistant/chunk","seq":129,"time":1783352102358,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":130,"time":1783352102358,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The read tool returned lines 5 through 8 as expected. Now I need to reply with exactly the single word \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":292,"outputTokens":30,"cacheReadTokens":2816,"reasoningTokens":27}},"sourceEventSeqs":[95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129],"surfaceOp":"append"}
+{"type":"assistant/message","seq":130,"time":1783352102358,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The read tool returned lines 5 through 8 as expected. Now I need to reply with exactly the single word \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":292,"outputTokens":30,"cacheReadTokens":2816,"reasoningTokens":27}},"sourceEventSeqs":[95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129],"surfaceOp":"append"}
 {"type":"step/end","seq":131,"time":1783352102358,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":132,"time":1783352102358,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/fs-read/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-read/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352072468,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352072469,"data":{"content":[{"type":"text","text":"Use the read tool (NOT bash) to read the file greeting.txt in the current directory, then reply with exactly the single word DONE."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352072470,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352072471,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352072471,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
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 {"type":"assistant/chunk","seq":5,"time":1783352073090,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352073210,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -51,7 +51,7 @@
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 {"type":"assistant/chunk","seq":51,"time":1783352073705,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":52,"time":1783352073708,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to read the file greeting.txt using the read tool (not bash), then reply with exactly the single word \"DONE\"."},{"type":"tool-call","id":"call_00_hHPZCcivsIkXAGS9jTGy8417","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}],"usage":{"inputTokens":2882,"outputTokens":75,"cacheReadTokens":0,"reasoningTokens":29}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
+{"type":"assistant/message","seq":52,"time":1783352073708,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to read the file greeting.txt using the read tool (not bash), then reply with exactly the single word \"DONE\"."},{"type":"tool-call","id":"call_00_hHPZCcivsIkXAGS9jTGy8417","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2882,"outputTokens":75,"cacheReadTokens":0,"reasoningTokens":29}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
 {"type":"tool/call","seq":53,"time":1783352073709,"data":{"turn":1,"step":1,"callId":"call_00_hHPZCcivsIkXAGS9jTGy8417","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}}
 {"type":"tool/result","seq":54,"time":1783352073717,"data":{"turn":1,"step":1,"callId":"call_00_hHPZCcivsIkXAGS9jTGy8417","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-PEETkS/greeting.txt</path>\n<type>file</type>\n<content>\n1: hello\n\n(End of file - total 1 lines)\n</content>"}],"isError":false},"sourceEventSeqs":[53],"surfaceOp":"append"}
 {"type":"step/end","seq":55,"time":1783352073718,"data":{"turn":1,"step":1}}
@@ -101,6 +101,6 @@
 {"type":"assistant/chunk","seq":99,"time":1783352075045,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":100,"time":1783352075045,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":200,"outputTokens":40,"cacheReadTokens":2816,"reasoningTokens":37}}}}
 {"type":"assistant/chunk","seq":101,"time":1783352075045,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":102,"time":1783352075045,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user asked me to read the file and then reply with exactly the single word \"DONE\". I've read the file. Now I just need to reply with \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":200,"outputTokens":40,"cacheReadTokens":2816,"reasoningTokens":37}},"sourceEventSeqs":[57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101],"surfaceOp":"append"}
+{"type":"assistant/message","seq":102,"time":1783352075045,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user asked me to read the file and then reply with exactly the single word \"DONE\". I've read the file. Now I just need to reply with \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":200,"outputTokens":40,"cacheReadTokens":2816,"reasoningTokens":37}},"sourceEventSeqs":[57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101],"surfaceOp":"append"}
 {"type":"step/end","seq":103,"time":1783352075046,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":104,"time":1783352075046,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/fs-terminal-card/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-terminal-card/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352050753,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352050753,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo TERMINAL_OK. Then reply with the single word DONE and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352050755,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352050756,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352050756,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352051421,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352051422,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352051590,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -58,7 +58,7 @@
 {"type":"assistant/chunk","seq":56,"time":1783352052118,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_fkbBRJsUrGKd1pWVc4Gn8233","name":"bash","arguments":"{\"command\": \"echo TERMINAL_OK\", \"description\": \"Echo TERMINAL_OK to verify terminal access\"}"}}}}
 {"type":"assistant/chunk","seq":57,"time":1783352052118,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2877,"outputTokens":90,"cacheReadTokens":0,"reasoningTokens":18}}}}
 {"type":"assistant/chunk","seq":58,"time":1783352052118,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":59,"time":1783352052121,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and then reply with \"DONE\"."},{"type":"tool-call","id":"call_00_fkbBRJsUrGKd1pWVc4Gn8233","name":"bash","arguments":"{\"command\": \"echo TERMINAL_OK\", \"description\": \"Echo TERMINAL_OK to verify terminal access\"}"}],"usage":{"inputTokens":2877,"outputTokens":90,"cacheReadTokens":0,"reasoningTokens":18}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58],"surfaceOp":"append"}
+{"type":"assistant/message","seq":59,"time":1783352052121,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and then reply with \"DONE\"."},{"type":"tool-call","id":"call_00_fkbBRJsUrGKd1pWVc4Gn8233","name":"bash","arguments":"{\"command\": \"echo TERMINAL_OK\", \"description\": \"Echo TERMINAL_OK to verify terminal access\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2877,"outputTokens":90,"cacheReadTokens":0,"reasoningTokens":18}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58],"surfaceOp":"append"}
 {"type":"tool/call","seq":60,"time":1783352052121,"data":{"turn":1,"step":1,"callId":"call_00_fkbBRJsUrGKd1pWVc4Gn8233","name":"bash","arguments":"{\"command\": \"echo TERMINAL_OK\", \"description\": \"Echo TERMINAL_OK to verify terminal access\"}"}}
 {"type":"tool/result","seq":61,"time":1783352052136,"data":{"turn":1,"step":1,"callId":"call_00_fkbBRJsUrGKd1pWVc4Gn8233","content":[{"type":"text","text":"TERMINAL_OK\n"}],"isError":false},"sourceEventSeqs":[60],"surfaceOp":"append"}
 {"type":"step/end","seq":62,"time":1783352052137,"data":{"turn":1,"step":1}}
@@ -93,6 +93,6 @@
 {"type":"assistant/chunk","seq":91,"time":1783352052986,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":92,"time":1783352052986,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":168,"outputTokens":25,"cacheReadTokens":2816,"reasoningTokens":22}}}}
 {"type":"assistant/chunk","seq":93,"time":1783352052986,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":94,"time":1783352052987,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command ran successfully and output \"TERMINAL_OK\". I should now reply with just \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":168,"outputTokens":25,"cacheReadTokens":2816,"reasoningTokens":22}},"sourceEventSeqs":[64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93],"surfaceOp":"append"}
+{"type":"assistant/message","seq":94,"time":1783352052987,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command ran successfully and output \"TERMINAL_OK\". I should now reply with just \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":168,"outputTokens":25,"cacheReadTokens":2816,"reasoningTokens":22}},"sourceEventSeqs":[64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93],"surfaceOp":"append"}
 {"type":"step/end","seq":95,"time":1783352052987,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":96,"time":1783352052987,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/fs-write-overwrite/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-write-overwrite/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352092220,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352092221,"data":{"content":[{"type":"text","text":"First use the read tool to read data.txt in the current directory. Then use the write tool (NOT bash) to replace its entire contents with exactly the single line: replaced. Then reply with exactly the single word DONE."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352092223,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352092223,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352092223,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352092902,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
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 {"type":"assistant/chunk","seq":6,"time":1783352093090,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -63,7 +63,7 @@
 {"type":"assistant/chunk","seq":61,"time":1783352093614,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_n4eRJuGoxNR07svgNtk82243","name":"read","arguments":"{\"file_path\": \"data.txt\"}"}}}}
 {"type":"assistant/chunk","seq":62,"time":1783352093614,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2899,"outputTokens":87,"cacheReadTokens":0,"reasoningTokens":42}}}}
 {"type":"assistant/chunk","seq":63,"time":1783352093614,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":64,"time":1783352093617,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Read data.txt using the read tool\n2. Replace its entire contents with exactly \"replaced\" using the write tool\n3. Reply with exactly \"DONE\""},{"type":"tool-call","id":"call_00_n4eRJuGoxNR07svgNtk82243","name":"read","arguments":"{\"file_path\": \"data.txt\"}"}],"usage":{"inputTokens":2899,"outputTokens":87,"cacheReadTokens":0,"reasoningTokens":42}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63],"surfaceOp":"append"}
+{"type":"assistant/message","seq":64,"time":1783352093617,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Read data.txt using the read tool\n2. Replace its entire contents with exactly \"replaced\" using the write tool\n3. Reply with exactly \"DONE\""},{"type":"tool-call","id":"call_00_n4eRJuGoxNR07svgNtk82243","name":"read","arguments":"{\"file_path\": \"data.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2899,"outputTokens":87,"cacheReadTokens":0,"reasoningTokens":42}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63],"surfaceOp":"append"}
 {"type":"tool/call","seq":65,"time":1783352093617,"data":{"turn":1,"step":1,"callId":"call_00_n4eRJuGoxNR07svgNtk82243","name":"read","arguments":"{\"file_path\": \"data.txt\"}"}}
 {"type":"tool/result","seq":66,"time":1783352093624,"data":{"turn":1,"step":1,"callId":"call_00_n4eRJuGoxNR07svgNtk82243","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-hH2sGY/data.txt</path>\n<type>file</type>\n<content>\n1: original contents\n\n(End of file - total 1 lines)\n</content>"}],"isError":false},"sourceEventSeqs":[65],"surfaceOp":"append"}
 {"type":"step/end","seq":67,"time":1783352093624,"data":{"turn":1,"step":1}}
@@ -112,7 +112,7 @@
 {"type":"assistant/chunk","seq":110,"time":1783352094988,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_N23EvXjDo4c8enyWpIUq4043","name":"write","arguments":"{\"file_path\": \"data.txt\", \"content\": \"replaced\"}"}}}}
 {"type":"assistant/chunk","seq":111,"time":1783352094988,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":228,"outputTokens":79,"cacheReadTokens":2816,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":112,"time":1783352094988,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":113,"time":1783352094988,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The file contains \"original contents\". Now I'll replace it with \"replaced\"."},{"type":"tool-call","id":"call_00_N23EvXjDo4c8enyWpIUq4043","name":"write","arguments":"{\"file_path\": \"data.txt\", \"content\": \"replaced\"}"}],"usage":{"inputTokens":228,"outputTokens":79,"cacheReadTokens":2816,"reasoningTokens":17}},"sourceEventSeqs":[69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112],"surfaceOp":"append"}
+{"type":"assistant/message","seq":113,"time":1783352094988,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The file contains \"original contents\". Now I'll replace it with \"replaced\"."},{"type":"tool-call","id":"call_00_N23EvXjDo4c8enyWpIUq4043","name":"write","arguments":"{\"file_path\": \"data.txt\", \"content\": \"replaced\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":228,"outputTokens":79,"cacheReadTokens":2816,"reasoningTokens":17}},"sourceEventSeqs":[69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112],"surfaceOp":"append"}
 {"type":"tool/call","seq":114,"time":1783352094988,"data":{"turn":1,"step":2,"callId":"call_00_N23EvXjDo4c8enyWpIUq4043","name":"write","arguments":"{\"file_path\": \"data.txt\", \"content\": \"replaced\"}"}}
 {"type":"tool/result","seq":115,"time":1783352094995,"data":{"turn":1,"step":2,"callId":"call_00_N23EvXjDo4c8enyWpIUq4043","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-hH2sGY/data.txt</path>\n<type>file</type>\n<content>\nUpdated file\n</content>"}],"isError":false,"meta":{"diffs":[{"path":"data.txt","oldText":"original contents","newText":"replaced"}]}},"sourceEventSeqs":[114],"surfaceOp":"append"}
 {"type":"step/end","seq":116,"time":1783352094995,"data":{"turn":1,"step":2}}
@@ -141,6 +141,6 @@
 {"type":"assistant/chunk","seq":139,"time":1783352096309,"data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":140,"time":1783352096309,"data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":225,"outputTokens":19,"cacheReadTokens":2944,"reasoningTokens":16}}}}
 {"type":"assistant/chunk","seq":141,"time":1783352096309,"data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":142,"time":1783352096310,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"The file has been replaced successfully. Now I just reply with \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":225,"outputTokens":19,"cacheReadTokens":2944,"reasoningTokens":16}},"sourceEventSeqs":[118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141],"surfaceOp":"append"}
+{"type":"assistant/message","seq":142,"time":1783352096310,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"The file has been replaced successfully. Now I just reply with \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":225,"outputTokens":19,"cacheReadTokens":2944,"reasoningTokens":16}},"sourceEventSeqs":[118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141],"surfaceOp":"append"}
 {"type":"step/end","seq":143,"time":1783352096310,"data":{"turn":1,"step":3}}
 {"type":"turn/end","seq":144,"time":1783352096310,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/fs-write/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/fs-write/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352078754,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352078754,"data":{"content":[{"type":"text","text":"Use the write tool (NOT bash) to create a file named notes.txt in the current directory containing exactly the single line: hello world. Then reply with exactly the single word DONE."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352078756,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352078756,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352078756,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352079254,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
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 {"type":"assistant/chunk","seq":6,"time":1783352079333,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -60,7 +60,7 @@
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 {"type":"assistant/chunk","seq":60,"time":1783352079886,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":61,"time":1783352079888,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to create a file named notes.txt with the content \"hello world\" using the write tool, then reply with \"DONE\"."},{"type":"tool-call","id":"call_00_APMUCJJm9lrTSlVbg6dB0185","name":"write","arguments":"{\"file_path\": \"notes.txt\", \"content\": \"hello world\"}"}],"usage":{"inputTokens":2891,"outputTokens":92,"cacheReadTokens":0,"reasoningTokens":30}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60],"surfaceOp":"append"}
+{"type":"assistant/message","seq":61,"time":1783352079888,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to create a file named notes.txt with the content \"hello world\" using the write tool, then reply with \"DONE\"."},{"type":"tool-call","id":"call_00_APMUCJJm9lrTSlVbg6dB0185","name":"write","arguments":"{\"file_path\": \"notes.txt\", \"content\": \"hello world\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2891,"outputTokens":92,"cacheReadTokens":0,"reasoningTokens":30}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60],"surfaceOp":"append"}
 {"type":"tool/call","seq":62,"time":1783352079888,"data":{"turn":1,"step":1,"callId":"call_00_APMUCJJm9lrTSlVbg6dB0185","name":"write","arguments":"{\"file_path\": \"notes.txt\", \"content\": \"hello world\"}"}}
 {"type":"tool/result","seq":63,"time":1783352079897,"data":{"turn":1,"step":1,"callId":"call_00_APMUCJJm9lrTSlVbg6dB0185","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-sNvn5N/notes.txt</path>\n<type>file</type>\n<content>\nCreated file\n</content>"}],"isError":false},"sourceEventSeqs":[62],"surfaceOp":"append"}
 {"type":"step/end","seq":64,"time":1783352079898,"data":{"turn":1,"step":1}}
@@ -90,6 +90,6 @@
 {"type":"assistant/chunk","seq":88,"time":1783352081056,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":89,"time":1783352081056,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":214,"outputTokens":20,"cacheReadTokens":2816,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":90,"time":1783352081056,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":91,"time":1783352081057,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The file has been created. Now I just need to reply with \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":214,"outputTokens":20,"cacheReadTokens":2816,"reasoningTokens":17}},"sourceEventSeqs":[66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90],"surfaceOp":"append"}
+{"type":"assistant/message","seq":91,"time":1783352081057,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The file has been created. Now I just need to reply with \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":214,"outputTokens":20,"cacheReadTokens":2816,"reasoningTokens":17}},"sourceEventSeqs":[66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90],"surfaceOp":"append"}
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--- a/examples/acp-agent/tests/snapshots/hook-cc-posttool-block/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-cc-posttool-block/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352177366,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352177367,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352177368,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352177372,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352177372,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
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 {"type":"assistant/chunk","seq":5,"time":1783352178018,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352178131,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -59,7 +59,7 @@
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+{"type":"assistant/message","seq":60,"time":1783352178594,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `echo HELLO` using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_qcIzLImnOm5qiKOBJUqY5047","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Echo HELLO to stdout\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2879,"outputTokens":91,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59],"surfaceOp":"append"}
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@@ -130,7 +130,7 @@
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+{"type":"assistant/message","seq":131,"time":1783352180489,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The tool output was rejected by policy, which says \"rerun with a summary instead\". Let me try again with a description that summarizes what we're doing."},{"type":"tool-call","id":"call_00_nzhKxYvCYj8OqI2tjOKb8506","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO command\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":178,"outputTokens":99,"cacheReadTokens":2816,"reasoningTokens":32}},"sourceEventSeqs":[67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130],"surfaceOp":"append"}
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@@ -182,7 +182,7 @@
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-{"type":"assistant/message","seq":183,"time":1783352181934,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"The tool keeps rejecting. Let me try a slightly different description."},{"type":"tool-call","id":"call_00_VumDDhhB4n5507EUXq650912","name":"bash","arguments":"{\"description\": \"Print HELLO to stdout\", \"command\": \"echo HELLO\"}"}],"usage":{"inputTokens":173,"outputTokens":80,"cacheReadTokens":2944,"reasoningTokens":13}},"sourceEventSeqs":[138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182],"surfaceOp":"append"}
+{"type":"assistant/message","seq":183,"time":1783352181934,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"The tool keeps rejecting. Let me try a slightly different description."},{"type":"tool-call","id":"call_00_VumDDhhB4n5507EUXq650912","name":"bash","arguments":"{\"description\": \"Print HELLO to stdout\", \"command\": \"echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":173,"outputTokens":80,"cacheReadTokens":2944,"reasoningTokens":13}},"sourceEventSeqs":[138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182],"surfaceOp":"append"}
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@@ -234,7 +234,7 @@
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@@ -280,7 +280,7 @@
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-{"type":"assistant/message","seq":281,"time":1783352184233,"data":{"turn":1,"step":5,"content":[{"type":"reasoning","text":"Hmm, the policy keeps rejecting. Let me try without the description field, just the command."},{"type":"tool-call","id":"call_00_0IuOIk6iuG6ZesROSyAM3669","name":"bash","arguments":"{\"command\": \"echo HELLO\"}"}],"usage":{"inputTokens":125,"outputTokens":66,"cacheReadTokens":3200,"reasoningTokens":20}},"sourceEventSeqs":[242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280],"surfaceOp":"append"}
+{"type":"assistant/message","seq":281,"time":1783352184233,"data":{"turn":1,"step":5,"content":[{"type":"reasoning","text":"Hmm, the policy keeps rejecting. Let me try without the description field, just the command."},{"type":"tool-call","id":"call_00_0IuOIk6iuG6ZesROSyAM3669","name":"bash","arguments":"{\"command\": \"echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":125,"outputTokens":66,"cacheReadTokens":3200,"reasoningTokens":20}},"sourceEventSeqs":[242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280],"surfaceOp":"append"}
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@@ -428,7 +428,7 @@
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+{"type":"assistant/message","seq":429,"time":1783352186527,"data":{"turn":1,"step":6,"content":[{"type":"reasoning","text":"The tool is consistently being rejected by policy. The policy says \"rerun with a summary instead\" - it seems the content of the output (which would be \"HELLO\") is being blocked. Let me try a different approach - maybe I need to use a different command or approach to satisfy the policy.\n\nWait, the user explicitly asked me to \"run exactly: echo HELLO\" and \"Report the tool result you got back verbatim\". Let me try `echo \"HELLO\"` with quotes."},{"type":"tool-call","id":"call_00_mGqWmySh60rWKNcyVBFk2747","name":"bash","arguments":"{\"description\": \"Echo the string HELLO\", \"command\": \"echo \\\"HELLO\\\"\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":215,"outputTokens":176,"cacheReadTokens":3200,"reasoningTokens":106}},"sourceEventSeqs":[288,289,290,291,292,293,294,295,296,297,298,299,300,301,302,303,304,305,306,307,308,309,310,311,312,313,314,315,316,317,318,319,320,321,322,323,324,325,326,327,328,329,330,331,332,333,334,335,336,337,338,339,340,341,342,343,344,345,346,347,348,349,350,351,352,353,354,355,356,357,358,359,360,361,362,363,364,365,366,367,368,369,370,371,372,373,374,375,376,377,378,379,380,381,382,383,384,385,386,387,388,389,390,391,392,393,394,395,396,397,398,399,400,401,402,403,404,405,406,407,408,409,410,411,412,413,414,415,416,417,418,419,420,421,422,423,424,425,426,427,428],"surfaceOp":"append"}
 {"type":"tool/call","seq":430,"time":1783352186527,"data":{"turn":1,"step":6,"callId":"call_00_mGqWmySh60rWKNcyVBFk2747","name":"bash","arguments":"{\"description\": \"Echo the string HELLO\", \"command\": \"echo \\\"HELLO\\\"\"}"}}
 {"type":"hook/invoked","seq":431,"time":1783352186538,"data":{"turn":1,"point":"PostToolUse","dialect":"claude","handlerId":"claude:PostToolUse:6","matcher":"bash"}}
 {"type":"hook/result","seq":432,"time":1783352186545,"data":{"turn":1,"point":"PostToolUse","handlerId":"claude:PostToolUse:6","decision":"block","exitCode":2,"stderrSummary":"tool output rejected by policy: rerun with a summary instead","durationMs":6.910448999999062}}
@@ -549,7 +549,7 @@
 {"type":"assistant/chunk","seq":547,"time":1783352188511,"data":{"turn":1,"step":7,"chunk":{"type":"block-end","index":2,"block":{"type":"tool-call","id":"call_00_Y371DzUR0Pz6IrkO8qgB9050","name":"bash","arguments":"{\"description\": \"Echo test message\", \"command\": \"echo \\\"TEST\\\"\"}"}}}}
 {"type":"assistant/chunk","seq":548,"time":1783352188511,"data":{"turn":1,"step":7,"chunk":{"type":"usage","usage":{"inputTokens":287,"outputTokens":146,"cacheReadTokens":3328,"reasoningTokens":70}}}}
 {"type":"assistant/chunk","seq":549,"time":1783352188512,"data":{"turn":1,"step":7,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":550,"time":1783352188512,"data":{"turn":1,"step":7,"content":[{"type":"reasoning","text":"The policy is blocking the output \"HELLO\" - it seems like the word \"HELLO\" (which might be a misspelling of \"HELLO\" that looks like \"HELL\" with \"O\") could be triggering some content filter. Let me try a completely different word to see if the tool works at all."},{"type":"text","text":"Let me try a different word to verify the tool works:"},{"type":"tool-call","id":"call_00_Y371DzUR0Pz6IrkO8qgB9050","name":"bash","arguments":"{\"description\": \"Echo test message\", \"command\": \"echo \\\"TEST\\\"\"}"}],"usage":{"inputTokens":287,"outputTokens":146,"cacheReadTokens":3328,"reasoningTokens":70}},"sourceEventSeqs":[436,437,438,439,440,441,442,443,444,445,446,447,448,449,450,451,452,453,454,455,456,457,458,459,460,461,462,463,464,465,466,467,468,469,470,471,472,473,474,475,476,477,478,479,480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,499,500,501,502,503,504,505,506,507,508,509,510,511,512,513,514,515,516,517,518,519,520,521,522,523,524,525,526,527,528,529,530,531,532,533,534,535,536,537,538,539,540,541,542,543,544,545,546,547,548,549],"surfaceOp":"append"}
+{"type":"assistant/message","seq":550,"time":1783352188512,"data":{"turn":1,"step":7,"content":[{"type":"reasoning","text":"The policy is blocking the output \"HELLO\" - it seems like the word \"HELLO\" (which might be a misspelling of \"HELLO\" that looks like \"HELL\" with \"O\") could be triggering some content filter. Let me try a completely different word to see if the tool works at all."},{"type":"text","text":"Let me try a different word to verify the tool works:"},{"type":"tool-call","id":"call_00_Y371DzUR0Pz6IrkO8qgB9050","name":"bash","arguments":"{\"description\": \"Echo test message\", \"command\": \"echo \\\"TEST\\\"\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":287,"outputTokens":146,"cacheReadTokens":3328,"reasoningTokens":70}},"sourceEventSeqs":[436,437,438,439,440,441,442,443,444,445,446,447,448,449,450,451,452,453,454,455,456,457,458,459,460,461,462,463,464,465,466,467,468,469,470,471,472,473,474,475,476,477,478,479,480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,499,500,501,502,503,504,505,506,507,508,509,510,511,512,513,514,515,516,517,518,519,520,521,522,523,524,525,526,527,528,529,530,531,532,533,534,535,536,537,538,539,540,541,542,543,544,545,546,547,548,549],"surfaceOp":"append"}
 {"type":"tool/call","seq":551,"time":1783352188512,"data":{"turn":1,"step":7,"callId":"call_00_Y371DzUR0Pz6IrkO8qgB9050","name":"bash","arguments":"{\"description\": \"Echo test message\", \"command\": \"echo \\\"TEST\\\"\"}"}}
 {"type":"hook/invoked","seq":552,"time":1783352188524,"data":{"turn":1,"point":"PostToolUse","dialect":"claude","handlerId":"claude:PostToolUse:7","matcher":"bash"}}
 {"type":"hook/result","seq":553,"time":1783352188532,"data":{"turn":1,"point":"PostToolUse","handlerId":"claude:PostToolUse:7","decision":"block","exitCode":2,"stderrSummary":"tool output rejected by policy: rerun with a summary instead","durationMs":7.573905000001105}}
@@ -605,7 +605,7 @@
 {"type":"assistant/chunk","seq":603,"time":1783352189858,"data":{"turn":1,"step":8,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_S2XENjVanaHtBn3RZfhO7965","name":"bash","arguments":"{\"description\": \"Print working directory\", \"command\": \"pwd\"}"}}}}
 {"type":"assistant/chunk","seq":604,"time":1783352189858,"data":{"turn":1,"step":8,"chunk":{"type":"usage","usage":{"inputTokens":201,"outputTokens":84,"cacheReadTokens":3584,"reasoningTokens":22}}}}
 {"type":"assistant/chunk","seq":605,"time":1783352189858,"data":{"turn":1,"step":8,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":606,"time":1783352189859,"data":{"turn":1,"step":8,"content":[{"type":"reasoning","text":"Even \"TEST\" is rejected. Let me try a simpler command like `pwd` or `ls`."},{"type":"tool-call","id":"call_00_S2XENjVanaHtBn3RZfhO7965","name":"bash","arguments":"{\"description\": \"Print working directory\", \"command\": \"pwd\"}"}],"usage":{"inputTokens":201,"outputTokens":84,"cacheReadTokens":3584,"reasoningTokens":22}},"sourceEventSeqs":[557,558,559,560,561,562,563,564,565,566,567,568,569,570,571,572,573,574,575,576,577,578,579,580,581,582,583,584,585,586,587,588,589,590,591,592,593,594,595,596,597,598,599,600,601,602,603,604,605],"surfaceOp":"append"}
+{"type":"assistant/message","seq":606,"time":1783352189859,"data":{"turn":1,"step":8,"content":[{"type":"reasoning","text":"Even \"TEST\" is rejected. Let me try a simpler command like `pwd` or `ls`."},{"type":"tool-call","id":"call_00_S2XENjVanaHtBn3RZfhO7965","name":"bash","arguments":"{\"description\": \"Print working directory\", \"command\": \"pwd\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":201,"outputTokens":84,"cacheReadTokens":3584,"reasoningTokens":22}},"sourceEventSeqs":[557,558,559,560,561,562,563,564,565,566,567,568,569,570,571,572,573,574,575,576,577,578,579,580,581,582,583,584,585,586,587,588,589,590,591,592,593,594,595,596,597,598,599,600,601,602,603,604,605],"surfaceOp":"append"}
 {"type":"tool/call","seq":607,"time":1783352189859,"data":{"turn":1,"step":8,"callId":"call_00_S2XENjVanaHtBn3RZfhO7965","name":"bash","arguments":"{\"description\": \"Print working directory\", \"command\": \"pwd\"}"}}
 {"type":"hook/invoked","seq":608,"time":1783352189876,"data":{"turn":1,"point":"PostToolUse","dialect":"claude","handlerId":"claude:PostToolUse:8","matcher":"bash"}}
 {"type":"hook/result","seq":609,"time":1783352189883,"data":{"turn":1,"point":"PostToolUse","handlerId":"claude:PostToolUse:8","decision":"block","exitCode":2,"stderrSummary":"tool output rejected by policy: rerun with a summary instead","durationMs":7.748225999999704}}
@@ -747,6 +747,6 @@
 {"type":"assistant/chunk","seq":745,"time":1783352192246,"data":{"turn":1,"step":9,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"I'm unable to run the `echo HELLO` command via the bash tool — every invocation is being rejected by the policy with the message \"tool output rejected by policy: rerun with a summary instead\". This appears to be a systemic policy restriction on the bash tool in this environment, as even simple commands like `pwd` and `echo \"TEST\"` are blocked.\n\nI cannot produce the tool result you asked for because the bash tool is not currently available for use."}}}}
 {"type":"assistant/chunk","seq":746,"time":1783352192246,"data":{"turn":1,"step":9,"chunk":{"type":"usage","usage":{"inputTokens":181,"outputTokens":130,"cacheReadTokens":3712,"reasoningTokens":31}}}}
 {"type":"assistant/chunk","seq":747,"time":1783352192246,"data":{"turn":1,"step":9,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":748,"time":1783352192247,"data":{"turn":1,"step":9,"content":[{"type":"reasoning","text":"All bash commands are being rejected. This seems like a system-level policy issue where the bash tool is blocked entirely. Let me report this to the user."},{"type":"text","text":"I'm unable to run the `echo HELLO` command via the bash tool — every invocation is being rejected by the policy with the message \"tool output rejected by policy: rerun with a summary instead\". This appears to be a systemic policy restriction on the bash tool in this environment, as even simple commands like `pwd` and `echo \"TEST\"` are blocked.\n\nI cannot produce the tool result you asked for because the bash tool is not currently available for use."}],"usage":{"inputTokens":181,"outputTokens":130,"cacheReadTokens":3712,"reasoningTokens":31}},"sourceEventSeqs":[613,614,615,616,617,618,619,620,621,622,623,624,625,626,627,628,629,630,631,632,633,634,635,636,637,638,639,640,641,642,643,644,645,646,647,648,649,650,651,652,653,654,655,656,657,658,659,660,661,662,663,664,665,666,667,668,669,670,671,672,673,674,675,676,677,678,679,680,681,682,683,684,685,686,687,688,689,690,691,692,693,694,695,696,697,698,699,700,701,702,703,704,705,706,707,708,709,710,711,712,713,714,715,716,717,718,719,720,721,722,723,724,725,726,727,728,729,730,731,732,733,734,735,736,737,738,739,740,741,742,743,744,745,746,747],"surfaceOp":"append"}
+{"type":"assistant/message","seq":748,"time":1783352192247,"data":{"turn":1,"step":9,"content":[{"type":"reasoning","text":"All bash commands are being rejected. This seems like a system-level policy issue where the bash tool is blocked entirely. Let me report this to the user."},{"type":"text","text":"I'm unable to run the `echo HELLO` command via the bash tool — every invocation is being rejected by the policy with the message \"tool output rejected by policy: rerun with a summary instead\". This appears to be a systemic policy restriction on the bash tool in this environment, as even simple commands like `pwd` and `echo \"TEST\"` are blocked.\n\nI cannot produce the tool result you asked for because the bash tool is not currently available for use."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":181,"outputTokens":130,"cacheReadTokens":3712,"reasoningTokens":31}},"sourceEventSeqs":[613,614,615,616,617,618,619,620,621,622,623,624,625,626,627,628,629,630,631,632,633,634,635,636,637,638,639,640,641,642,643,644,645,646,647,648,649,650,651,652,653,654,655,656,657,658,659,660,661,662,663,664,665,666,667,668,669,670,671,672,673,674,675,676,677,678,679,680,681,682,683,684,685,686,687,688,689,690,691,692,693,694,695,696,697,698,699,700,701,702,703,704,705,706,707,708,709,710,711,712,713,714,715,716,717,718,719,720,721,722,723,724,725,726,727,728,729,730,731,732,733,734,735,736,737,738,739,740,741,742,743,744,745,746,747],"surfaceOp":"append"}
 {"type":"step/end","seq":749,"time":1783352192247,"data":{"turn":1,"step":9}}
 {"type":"turn/end","seq":750,"time":1783352192247,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-cc-posttool-context/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-cc-posttool-context/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352196662,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352196662,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352196664,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352196664,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352196664,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352197315,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352197315,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352197457,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -57,7 +57,7 @@
 {"type":"assistant/chunk","seq":55,"time":1783352197953,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_HbCMzTslWBZTSphWN0z97382","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}}}
 {"type":"assistant/chunk","seq":56,"time":1783352197953,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2878,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":23}}}}
 {"type":"assistant/chunk","seq":57,"time":1783352197954,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":58,"time":1783352197956,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `echo HELLO` using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_HbCMzTslWBZTSphWN0z97382","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"usage":{"inputTokens":2878,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57],"surfaceOp":"append"}
+{"type":"assistant/message","seq":58,"time":1783352197956,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `echo HELLO` using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_HbCMzTslWBZTSphWN0z97382","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2878,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57],"surfaceOp":"append"}
 {"type":"tool/call","seq":59,"time":1783352197956,"data":{"turn":1,"step":1,"callId":"call_00_HbCMzTslWBZTSphWN0z97382","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}
 {"type":"hook/invoked","seq":60,"time":1783352197968,"data":{"turn":1,"point":"PostToolUse","dialect":"claude","handlerId":"claude:PostToolUse:1","matcher":"bash"}}
 {"type":"hook/result","seq":61,"time":1783352197976,"data":{"turn":1,"point":"PostToolUse","handlerId":"claude:PostToolUse:1","decision":"pass","exitCode":0,"durationMs":7.404540999999881}}
@@ -121,6 +121,6 @@
 {"type":"assistant/chunk","seq":119,"time":1783352199410,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The tool result was:\n\n```\nHELLO\n```\n\nIt completed successfully with exit code 0."}}}}
 {"type":"assistant/chunk","seq":120,"time":1783352199411,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":188,"outputTokens":51,"cacheReadTokens":2816,"reasoningTokens":30}}}}
 {"type":"assistant/chunk","seq":121,"time":1783352199411,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":122,"time":1783352199411,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user asked me to report the tool result verbatim. The result was \"HELLO\" with an exit code of 0 (success)."},{"type":"text","text":"The tool result was:\n\n```\nHELLO\n```\n\nIt completed successfully with exit code 0."}],"usage":{"inputTokens":188,"outputTokens":51,"cacheReadTokens":2816,"reasoningTokens":30}},"sourceEventSeqs":[66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121],"surfaceOp":"append"}
+{"type":"assistant/message","seq":122,"time":1783352199411,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user asked me to report the tool result verbatim. The result was \"HELLO\" with an exit code of 0 (success)."},{"type":"text","text":"The tool result was:\n\n```\nHELLO\n```\n\nIt completed successfully with exit code 0."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":188,"outputTokens":51,"cacheReadTokens":2816,"reasoningTokens":30}},"sourceEventSeqs":[66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121],"surfaceOp":"append"}
 {"type":"step/end","seq":123,"time":1783352199411,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":124,"time":1783352199412,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-cc-pretool-ask/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-cc-pretool-ask/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352171519,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352171520,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352171527,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352171528,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352171528,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352171991,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
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 {"type":"assistant/chunk","seq":6,"time":1783352172088,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -51,7 +51,7 @@
 {"type":"assistant/chunk","seq":49,"time":1783352172555,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_6k0oGSliVHxGSgqBmMEO4311","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Echo HELLO\"}"}}}}
 {"type":"assistant/chunk","seq":50,"time":1783352172555,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2878,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":51,"time":1783352172555,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":52,"time":1783352172557,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and report the result verbatim."},{"type":"tool-call","id":"call_00_6k0oGSliVHxGSgqBmMEO4311","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Echo HELLO\"}"}],"usage":{"inputTokens":2878,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
+{"type":"assistant/message","seq":52,"time":1783352172557,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and report the result verbatim."},{"type":"tool-call","id":"call_00_6k0oGSliVHxGSgqBmMEO4311","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2878,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
 {"type":"tool/call","seq":53,"time":1783352172557,"data":{"turn":1,"step":1,"callId":"call_00_6k0oGSliVHxGSgqBmMEO4311","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Echo HELLO\"}"}}
 {"type":"hook/invoked","seq":54,"time":1783352172558,"data":{"turn":1,"point":"PreToolUse","dialect":"claude","handlerId":"claude:PreToolUse:1","matcher":"bash"}}
 {"type":"hook/result","seq":55,"time":1783352172573,"data":{"turn":1,"point":"PreToolUse","handlerId":"claude:PreToolUse:1","decision":"ask","exitCode":0,"durationMs":14.113374999999905}}
@@ -108,6 +108,6 @@
 {"type":"assistant/chunk","seq":106,"time":1783352173964,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The tool result I got back verbatim is:\n\n```\nError: bash requires manual approval in this session\n```"}}}}
 {"type":"assistant/chunk","seq":107,"time":1783352173964,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":166,"outputTokens":45,"cacheReadTokens":2816,"reasoningTokens":22}}}}
 {"type":"assistant/chunk","seq":108,"time":1783352173964,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":109,"time":1783352173964,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The bash tool returned an error saying it requires manual approval in this session. I'll report this verbatim."},{"type":"text","text":"The tool result I got back verbatim is:\n\n```\nError: bash requires manual approval in this session\n```"}],"usage":{"inputTokens":166,"outputTokens":45,"cacheReadTokens":2816,"reasoningTokens":22}},"sourceEventSeqs":[59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108],"surfaceOp":"append"}
+{"type":"assistant/message","seq":109,"time":1783352173964,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The bash tool returned an error saying it requires manual approval in this session. I'll report this verbatim."},{"type":"text","text":"The tool result I got back verbatim is:\n\n```\nError: bash requires manual approval in this session\n```"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":166,"outputTokens":45,"cacheReadTokens":2816,"reasoningTokens":22}},"sourceEventSeqs":[59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108],"surfaceOp":"append"}
 {"type":"step/end","seq":110,"time":1783352173964,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":111,"time":1783352173965,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-cc-pretool-deny/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-cc-pretool-deny/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352165195,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352165196,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352165198,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352165199,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352165199,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352165899,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352165899,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352166048,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -51,7 +51,7 @@
 {"type":"assistant/chunk","seq":49,"time":1783352166512,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_JliP571Bh0QQ8QExbSPk0080","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}}}
 {"type":"assistant/chunk","seq":50,"time":1783352166512,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2878,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":51,"time":1783352166512,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":52,"time":1783352166514,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and report the result verbatim."},{"type":"tool-call","id":"call_00_JliP571Bh0QQ8QExbSPk0080","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"usage":{"inputTokens":2878,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
+{"type":"assistant/message","seq":52,"time":1783352166514,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and report the result verbatim."},{"type":"tool-call","id":"call_00_JliP571Bh0QQ8QExbSPk0080","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2878,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
 {"type":"tool/call","seq":53,"time":1783352166514,"data":{"turn":1,"step":1,"callId":"call_00_JliP571Bh0QQ8QExbSPk0080","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}
 {"type":"hook/invoked","seq":54,"time":1783352166515,"data":{"turn":1,"point":"PreToolUse","dialect":"claude","handlerId":"claude:PreToolUse:1","matcher":"bash"}}
 {"type":"hook/result","seq":55,"time":1783352166528,"data":{"turn":1,"point":"PreToolUse","handlerId":"claude:PreToolUse:1","decision":"block","exitCode":2,"stderrSummary":"bash is disabled by policy in this session","durationMs":12.367074000000684}}
@@ -115,6 +115,6 @@
 {"type":"assistant/chunk","seq":113,"time":1783352167933,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The tool returned:\n\n> Error: bash is disabled by policy in this session\n\nI cannot run the command because the bash tool is disabled by policy."}}}}
 {"type":"assistant/chunk","seq":114,"time":1783352167933,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":167,"outputTokens":52,"cacheReadTokens":2816,"reasoningTokens":21}}}}
 {"type":"assistant/chunk","seq":115,"time":1783352167933,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":116,"time":1783352167934,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The bash tool is disabled by policy. I need to report this error verbatim back to the user."},{"type":"text","text":"The tool returned:\n\n> Error: bash is disabled by policy in this session\n\nI cannot run the command because the bash tool is disabled by policy."}],"usage":{"inputTokens":167,"outputTokens":52,"cacheReadTokens":2816,"reasoningTokens":21}},"sourceEventSeqs":[59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115],"surfaceOp":"append"}
+{"type":"assistant/message","seq":116,"time":1783352167934,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The bash tool is disabled by policy. I need to report this error verbatim back to the user."},{"type":"text","text":"The tool returned:\n\n> Error: bash is disabled by policy in this session\n\nI cannot run the command because the bash tool is disabled by policy."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":167,"outputTokens":52,"cacheReadTokens":2816,"reasoningTokens":21}},"sourceEventSeqs":[59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115],"surfaceOp":"append"}
 {"type":"step/end","seq":117,"time":1783352167934,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":118,"time":1783352167934,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-cc-promptsubmit-context/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-cc-promptsubmit-context/session.jsonl
@@ -5,7 +5,7 @@
 {"type":"user/message","seq":3,"time":1783352160564,"data":{"content":[{"type":"text","text":"What is my favorite color? Reply with just the color and stop. Do not use any tools."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"context/message","seq":4,"time":1783352160564,"data":{"content":[{"type":"text","text":"The user has previously stated their favorite color is teal."}],"source":{"kind":"plugin","plugin":"hooks-claude"}},"surfaceOp":"append"}
 {"type":"step/start","seq":5,"time":1783352160565,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":6,"time":1783352160566,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":6,"time":1783352160566,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":7,"time":1783352161228,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":8,"time":1783352161229,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":9,"time":1783352161335,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -33,6 +33,6 @@
 {"type":"assistant/chunk","seq":31,"time":1783352161512,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"teal"}}}}
 {"type":"assistant/chunk","seq":32,"time":1783352161512,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2892,"outputTokens":22,"cacheReadTokens":0,"reasoningTokens":19}}}}
 {"type":"assistant/chunk","seq":33,"time":1783352161512,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":34,"time":1783352161515,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user's favorite color is teal, as stated in the context provided by the plugin."},{"type":"text","text":"teal"}],"usage":{"inputTokens":2892,"outputTokens":22,"cacheReadTokens":0,"reasoningTokens":19}},"sourceEventSeqs":[7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33],"surfaceOp":"append"}
+{"type":"assistant/message","seq":34,"time":1783352161515,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user's favorite color is teal, as stated in the context provided by the plugin."},{"type":"text","text":"teal"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2892,"outputTokens":22,"cacheReadTokens":0,"reasoningTokens":19}},"sourceEventSeqs":[7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33],"surfaceOp":"append"}
 {"type":"step/end","seq":35,"time":1783352161516,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":36,"time":1783352161516,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-cc-stop-continue/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-cc-stop-continue/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352203369,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352203370,"data":{"content":[{"type":"text","text":"Reply with the single word FIRST and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352203371,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352203372,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352203372,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352204036,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352204036,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352204247,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -28,7 +28,7 @@
 {"type":"assistant/chunk","seq":26,"time":1783352204393,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"FIRST"}}}}
 {"type":"assistant/chunk","seq":27,"time":1783352204393,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2862,"outputTokens":20,"cacheReadTokens":0,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":28,"time":1783352204393,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":29,"time":1783352204396,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with the single word \"FIRST\" and stop."},{"type":"text","text":"FIRST"}],"usage":{"inputTokens":2862,"outputTokens":20,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28],"surfaceOp":"append"}
+{"type":"assistant/message","seq":29,"time":1783352204396,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with the single word \"FIRST\" and stop."},{"type":"text","text":"FIRST"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2862,"outputTokens":20,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28],"surfaceOp":"append"}
 {"type":"step/end","seq":30,"time":1783352204396,"data":{"turn":1,"step":1}}
 {"type":"hook/invoked","seq":31,"time":1783352204396,"data":{"turn":1,"point":"Stop","dialect":"claude","handlerId":"claude:Stop:1"}}
 {"type":"hook/result","seq":32,"time":1783352204443,"data":{"turn":1,"point":"Stop","handlerId":"claude:Stop:1","decision":"block","exitCode":2,"stderrSummary":"Also reply with the single word SECOND, then stop.","durationMs":47.01462700000047}}
@@ -185,7 +185,7 @@
 {"type":"assistant/chunk","seq":183,"time":1783352206162,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"FIRST"}}}}
 {"type":"assistant/chunk","seq":184,"time":1783352206162,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":73,"outputTokens":146,"cacheReadTokens":2816,"reasoningTokens":143}}}}
 {"type":"assistant/chunk","seq":185,"time":1783352206162,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":186,"time":1783352206162,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user wants me to reply with \"FIRST\" only, but there's a steering input telling me to also reply with \"SECOND\". However, the user's explicit instruction is to reply with the single word FIRST and stop. The steering is from a plugin, not the user themselves. I should follow the user's original instruction.\n\nWait, let me re-read. The user said \"Reply with the single word FIRST and stop.\" Then there's a steering from \"plugin\" saying \"Also reply with the single word SECOND, then stop.\"\n\nThe user's instruction is clear: reply with FIRST and stop. The steering is from a plugin source, not the user. I'll follow the user's instruction."},{"type":"text","text":"FIRST"}],"usage":{"inputTokens":73,"outputTokens":146,"cacheReadTokens":2816,"reasoningTokens":143}},"sourceEventSeqs":[35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185],"surfaceOp":"append"}
+{"type":"assistant/message","seq":186,"time":1783352206162,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user wants me to reply with \"FIRST\" only, but there's a steering input telling me to also reply with \"SECOND\". However, the user's explicit instruction is to reply with the single word FIRST and stop. The steering is from a plugin, not the user themselves. I should follow the user's original instruction.\n\nWait, let me re-read. The user said \"Reply with the single word FIRST and stop.\" Then there's a steering from \"plugin\" saying \"Also reply with the single word SECOND, then stop.\"\n\nThe user's instruction is clear: reply with FIRST and stop. The steering is from a plugin source, not the user. I'll follow the user's instruction."},{"type":"text","text":"FIRST"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":73,"outputTokens":146,"cacheReadTokens":2816,"reasoningTokens":143}},"sourceEventSeqs":[35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185],"surfaceOp":"append"}
 {"type":"step/end","seq":187,"time":1783352206163,"data":{"turn":1,"step":2}}
 {"type":"hook/invoked","seq":188,"time":1783352206163,"data":{"turn":1,"point":"Stop","dialect":"claude","handlerId":"claude:Stop:2"}}
 {"type":"hook/result","seq":189,"time":1783352206190,"data":{"turn":1,"point":"Stop","handlerId":"claude:Stop:2","decision":"pass","exitCode":0,"durationMs":26.904655000000275}}
--- a/examples/acp-agent/tests/snapshots/hook-codex-posttool-block/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-codex-posttool-block/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352220747,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352220748,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352220749,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352220750,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352220750,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352221451,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352221451,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352221651,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -60,7 +60,7 @@
 {"type":"assistant/chunk","seq":58,"time":1783352222121,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_wNJIQDMLdssZp45zIXvz2684","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Print HELLO to stdout\"}"}}}}
 {"type":"assistant/chunk","seq":59,"time":1783352222121,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2878,"outputTokens":92,"cacheReadTokens":0,"reasoningTokens":25}}}}
 {"type":"assistant/chunk","seq":60,"time":1783352222121,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":61,"time":1783352222124,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run the command \"echo HELLO\" using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_wNJIQDMLdssZp45zIXvz2684","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Print HELLO to stdout\"}"}],"usage":{"inputTokens":2878,"outputTokens":92,"cacheReadTokens":0,"reasoningTokens":25}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60],"surfaceOp":"append"}
+{"type":"assistant/message","seq":61,"time":1783352222124,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run the command \"echo HELLO\" using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_wNJIQDMLdssZp45zIXvz2684","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Print HELLO to stdout\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2878,"outputTokens":92,"cacheReadTokens":0,"reasoningTokens":25}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60],"surfaceOp":"append"}
 {"type":"tool/call","seq":62,"time":1783352222124,"data":{"turn":1,"step":1,"callId":"call_00_wNJIQDMLdssZp45zIXvz2684","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Print HELLO to stdout\"}"}}
 {"type":"hook/invoked","seq":63,"time":1783352222138,"data":{"turn":1,"point":"PostToolUse","dialect":"codex","handlerId":"codex:PostToolUse:1","matcher":"bash"}}
 {"type":"hook/result","seq":64,"time":1783352222148,"data":{"turn":1,"point":"PostToolUse","handlerId":"codex:PostToolUse:1","decision":"block","exitCode":2,"stderrSummary":"tool output rejected by codex policy: summarize instead","durationMs":9.571565000000192}}
@@ -217,6 +217,6 @@
 {"type":"assistant/chunk","seq":215,"time":1783352224654,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The tool result I got back is:\n\n> `tool output rejected by codex policy: summarize instead`\n\nThis is the verbatim result from the tool — it was not the expected `\"HELLO\"` output because the codex policy blocked it and instructed me to summarize instead."}}}}
 {"type":"assistant/chunk","seq":216,"time":1783352224654,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":176,"outputTokens":145,"cacheReadTokens":2816,"reasoningTokens":86}}}}
 {"type":"assistant/chunk","seq":217,"time":1783352224654,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":218,"time":1783352224655,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The output was rejected by the codex policy with the instruction to \"summarize instead\". This means I cannot show the raw output verbatim as the user requested. Let me try to comply but report what happened.\n\nActually, the user asked me to report the tool result verbatim. The tool result I got back is:\n\n\"tool output rejected by codex policy: summarize instead\"\n\nSo I should report that verbatim."},{"type":"text","text":"The tool result I got back is:\n\n> `tool output rejected by codex policy: summarize instead`\n\nThis is the verbatim result from the tool — it was not the expected `\"HELLO\"` output because the codex policy blocked it and instructed me to summarize instead."}],"usage":{"inputTokens":176,"outputTokens":145,"cacheReadTokens":2816,"reasoningTokens":86}},"sourceEventSeqs":[68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217],"surfaceOp":"append"}
+{"type":"assistant/message","seq":218,"time":1783352224655,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The output was rejected by the codex policy with the instruction to \"summarize instead\". This means I cannot show the raw output verbatim as the user requested. Let me try to comply but report what happened.\n\nActually, the user asked me to report the tool result verbatim. The tool result I got back is:\n\n\"tool output rejected by codex policy: summarize instead\"\n\nSo I should report that verbatim."},{"type":"text","text":"The tool result I got back is:\n\n> `tool output rejected by codex policy: summarize instead`\n\nThis is the verbatim result from the tool — it was not the expected `\"HELLO\"` output because the codex policy blocked it and instructed me to summarize instead."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":176,"outputTokens":145,"cacheReadTokens":2816,"reasoningTokens":86}},"sourceEventSeqs":[68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217],"surfaceOp":"append"}
 {"type":"step/end","seq":219,"time":1783352224655,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":220,"time":1783352224655,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-codex-posttool-context/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-codex-posttool-context/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352228441,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352228442,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352228443,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352228443,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352228443,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352228985,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352228985,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352229106,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -57,7 +57,7 @@
 {"type":"assistant/chunk","seq":55,"time":1783352229598,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_Q6wHtakaip2QNfIXaVJY5458","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}}}
 {"type":"assistant/chunk","seq":56,"time":1783352229598,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2878,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":23}}}}
 {"type":"assistant/chunk","seq":57,"time":1783352229598,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":58,"time":1783352229601,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `echo HELLO` using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_Q6wHtakaip2QNfIXaVJY5458","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"usage":{"inputTokens":2878,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57],"surfaceOp":"append"}
+{"type":"assistant/message","seq":58,"time":1783352229601,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `echo HELLO` using the bash tool and report the result verbatim."},{"type":"tool-call","id":"call_00_Q6wHtakaip2QNfIXaVJY5458","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2878,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57],"surfaceOp":"append"}
 {"type":"tool/call","seq":59,"time":1783352229601,"data":{"turn":1,"step":1,"callId":"call_00_Q6wHtakaip2QNfIXaVJY5458","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}
 {"type":"hook/invoked","seq":60,"time":1783352229622,"data":{"turn":1,"point":"PostToolUse","dialect":"codex","handlerId":"codex:PostToolUse:1","matcher":"bash"}}
 {"type":"hook/result","seq":61,"time":1783352229632,"data":{"turn":1,"point":"PostToolUse","handlerId":"codex:PostToolUse:1","decision":"pass","exitCode":0,"durationMs":9.27664199999981}}
@@ -111,6 +111,6 @@
 {"type":"assistant/chunk","seq":109,"time":1783352231379,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The tool result I received is:\n\n```\nHELLO\n```"}}}}
 {"type":"assistant/chunk","seq":110,"time":1783352231379,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":188,"outputTokens":41,"cacheReadTokens":2816,"reasoningTokens":27}}}}
 {"type":"assistant/chunk","seq":111,"time":1783352231379,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":112,"time":1783352231380,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user asked me to report the tool result verbatim. The result I got back is:\n\nHELLO\n\nThat's it."},{"type":"text","text":"The tool result I received is:\n\n```\nHELLO\n```"}],"usage":{"inputTokens":188,"outputTokens":41,"cacheReadTokens":2816,"reasoningTokens":27}},"sourceEventSeqs":[66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111],"surfaceOp":"append"}
+{"type":"assistant/message","seq":112,"time":1783352231380,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user asked me to report the tool result verbatim. The result I got back is:\n\nHELLO\n\nThat's it."},{"type":"text","text":"The tool result I received is:\n\n```\nHELLO\n```"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":188,"outputTokens":41,"cacheReadTokens":2816,"reasoningTokens":27}},"sourceEventSeqs":[66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111],"surfaceOp":"append"}
 {"type":"step/end","seq":113,"time":1783352231380,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":114,"time":1783352231380,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-codex-pretool-block/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-codex-pretool-block/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352214604,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352214605,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo HELLO. Report the tool result you got back verbatim, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352214607,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352214608,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352214608,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352215181,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352215181,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352215351,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -51,7 +51,7 @@
 {"type":"assistant/chunk","seq":49,"time":1783352215801,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_tv0SMeLXaTuyuVrOxnV97085","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}}}
 {"type":"assistant/chunk","seq":50,"time":1783352215801,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2880,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":51,"time":1783352215801,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":52,"time":1783352215804,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and report the result verbatim."},{"type":"tool-call","id":"call_00_tv0SMeLXaTuyuVrOxnV97085","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"usage":{"inputTokens":2880,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
+{"type":"assistant/message","seq":52,"time":1783352215804,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a simple bash command and report the result verbatim."},{"type":"tool-call","id":"call_00_tv0SMeLXaTuyuVrOxnV97085","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2880,"outputTokens":83,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51],"surfaceOp":"append"}
 {"type":"tool/call","seq":53,"time":1783352215804,"data":{"turn":1,"step":1,"callId":"call_00_tv0SMeLXaTuyuVrOxnV97085","name":"bash","arguments":"{\"command\": \"echo HELLO\", \"description\": \"Run echo HELLO\"}"}}
 {"type":"hook/invoked","seq":54,"time":1783352215805,"data":{"turn":1,"point":"PreToolUse","dialect":"codex","handlerId":"codex:PreToolUse:1","matcher":"bash"}}
 {"type":"hook/result","seq":55,"time":1783352215832,"data":{"turn":1,"point":"PreToolUse","handlerId":"codex:PreToolUse:1","decision":"block","exitCode":2,"stderrSummary":"bash is disabled by codex policy in this session","durationMs":26.08518500000082}}
@@ -112,6 +112,6 @@
 {"type":"assistant/chunk","seq":110,"time":1783352217214,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The tool result I got back verbatim is:\n\n```\nError: bash is disabled by codex policy in this session\n```"}}}}
 {"type":"assistant/chunk","seq":111,"time":1783352217214,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":171,"outputTokens":49,"cacheReadTokens":2816,"reasoningTokens":23}}}}
 {"type":"assistant/chunk","seq":112,"time":1783352217214,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":113,"time":1783352217214,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The bash tool is disabled by policy in this session. I need to report this result verbatim to the user."},{"type":"text","text":"The tool result I got back verbatim is:\n\n```\nError: bash is disabled by codex policy in this session\n```"}],"usage":{"inputTokens":171,"outputTokens":49,"cacheReadTokens":2816,"reasoningTokens":23}},"sourceEventSeqs":[59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112],"surfaceOp":"append"}
+{"type":"assistant/message","seq":113,"time":1783352217214,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The bash tool is disabled by policy in this session. I need to report this result verbatim to the user."},{"type":"text","text":"The tool result I got back verbatim is:\n\n```\nError: bash is disabled by codex policy in this session\n```"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":171,"outputTokens":49,"cacheReadTokens":2816,"reasoningTokens":23}},"sourceEventSeqs":[59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112],"surfaceOp":"append"}
 {"type":"step/end","seq":114,"time":1783352217215,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":115,"time":1783352217215,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/hook-codex-promptsubmit-context/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-codex-promptsubmit-context/session.jsonl
@@ -5,7 +5,7 @@
 {"type":"user/message","seq":3,"time":1783352209707,"data":{"content":[{"type":"text","text":"What is my favorite color? Reply with just the color and stop. Do not use any tools."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"context/message","seq":4,"time":1783352209707,"data":{"content":[{"type":"text","text":"The user has previously stated their favorite color is teal."}],"source":{"kind":"plugin","plugin":"hooks-codex"}},"surfaceOp":"append"}
 {"type":"step/start","seq":5,"time":1783352209709,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":6,"time":1783352209710,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":6,"time":1783352209710,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":7,"time":1783352210353,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":8,"time":1783352210353,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":9,"time":1783352210470,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -52,6 +52,6 @@
 {"type":"assistant/chunk","seq":50,"time":1783352210788,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"teal"}}}}
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--- a/examples/acp-agent/tests/snapshots/hook-codex-stop-continue/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/hook-codex-stop-continue/session.jsonl
@@ -2,7 +2,7 @@
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@@ -30,7 +30,7 @@
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@@ -60,7 +60,7 @@
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+{"type":"assistant/message","seq":61,"time":1783352236877,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user is asking me to reply with the single word SECOND, then stop."},{"type":"text","text":"SECOND"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":73,"outputTokens":19,"cacheReadTokens":2816,"reasoningTokens":16}},"sourceEventSeqs":[37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60],"surfaceOp":"append"}
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--- a/examples/acp-agent/tests/snapshots/multi-turn/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/multi-turn/session.jsonl
@@ -2,7 +2,7 @@
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@@ -28,7 +28,7 @@
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@@ -60,6 +60,6 @@
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--- a/examples/acp-agent/tests/snapshots/repeat-tool-guard/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/repeat-tool-guard/session.jsonl
@@ -2,13 +2,13 @@
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+{"type":"assistant/message","seq":66,"time":0,"data":{"turn":1,"step":6,"content":[{"type":"text","text":"DONE."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":10,"outputTokens":3}},"sourceEventSeqs":[61,62,63,64,65],"surfaceOp":"append"}
 {"type":"step/end","seq":67,"time":0,"data":{"turn":1,"step":6}}
 {"type":"turn/end","seq":68,"time":0,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/skill-load/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/skill-load/session.jsonl
--- a/examples/acp-agent/tests/snapshots/subagent-fork/session.1.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-fork/session.1.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352134837,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352134838,"data":{"content":[{"type":"text","text":"Remember this fact for later: the project codeword is MARMALADE. Reply with the single word OK and stop. Do not use any tools."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352134840,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352134840,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352134840,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
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 {"type":"assistant/chunk","seq":6,"time":1783352135621,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -33,13 +33,13 @@
 {"type":"assistant/chunk","seq":31,"time":1783352135771,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"OK"}}}}
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-{"type":"assistant/message","seq":34,"time":1783352135773,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember the codeword \"MARMALADE\" and reply with just \"OK\"."},{"type":"text","text":"OK"}],"usage":{"inputTokens":2885,"outputTokens":25,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33],"surfaceOp":"append"}
+{"type":"assistant/message","seq":34,"time":1783352135773,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember the codeword \"MARMALADE\" and reply with just \"OK\"."},{"type":"text","text":"OK"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2885,"outputTokens":25,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33],"surfaceOp":"append"}
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 {"type":"step/start","seq":39,"time":1783352137163,"data":{"turn":2,"step":1}}
-{"type":"request/header","seq":40,"time":1783352137163,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"resume"}}
+{"type":"request/header","seq":40,"time":1783352137163,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"resume"}}
 {"type":"assistant/chunk","seq":41,"time":1783352137783,"data":{"turn":2,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
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 {"type":"assistant/chunk","seq":43,"time":1783352137961,"data":{"turn":2,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -84,6 +84,6 @@
 {"type":"assistant/chunk","seq":82,"time":1783352138307,"data":{"turn":2,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"MARMALADE"}}}}
 {"type":"assistant/chunk","seq":83,"time":1783352138307,"data":{"turn":2,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":97,"outputTokens":39,"cacheReadTokens":2816,"reasoningTokens":34}}}}
 {"type":"assistant/chunk","seq":84,"time":1783352138307,"data":{"turn":2,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":85,"time":1783352138308,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user asked me to remember the project codeword \"MARMALADE\" and now they're asking what it is. I should just reply with that word."},{"type":"text","text":"MARMALADE"}],"usage":{"inputTokens":97,"outputTokens":39,"cacheReadTokens":2816,"reasoningTokens":34}},"sourceEventSeqs":[41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84],"surfaceOp":"append"}
+{"type":"assistant/message","seq":85,"time":1783352138308,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user asked me to remember the project codeword \"MARMALADE\" and now they're asking what it is. I should just reply with that word."},{"type":"text","text":"MARMALADE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":97,"outputTokens":39,"cacheReadTokens":2816,"reasoningTokens":34}},"sourceEventSeqs":[41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84],"surfaceOp":"append"}
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 {"type":"turn/end","seq":87,"time":1783352138308,"data":{"turn":2,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-fork/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-fork/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352134837,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352134838,"data":{"content":[{"type":"text","text":"Remember this fact for later: the project codeword is MARMALADE. Reply with the single word OK and stop. Do not use any tools."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352134840,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352134840,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352134840,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352135465,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
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@@ -33,7 +33,7 @@
 {"type":"assistant/chunk","seq":31,"time":1783352135771,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"OK"}}}}
 {"type":"assistant/chunk","seq":32,"time":1783352135771,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2885,"outputTokens":25,"cacheReadTokens":0,"reasoningTokens":23}}}}
 {"type":"assistant/chunk","seq":33,"time":1783352135771,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":34,"time":1783352135773,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember the codeword \"MARMALADE\" and reply with just \"OK\"."},{"type":"text","text":"OK"}],"usage":{"inputTokens":2885,"outputTokens":25,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33],"surfaceOp":"append"}
+{"type":"assistant/message","seq":34,"time":1783352135773,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember the codeword \"MARMALADE\" and reply with just \"OK\"."},{"type":"text","text":"OK"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2885,"outputTokens":25,"cacheReadTokens":0,"reasoningTokens":23}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33],"surfaceOp":"append"}
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@@ -149,7 +149,7 @@
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-{"type":"assistant/message","seq":150,"time":1783352137159,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use subagent_fork to delegate a question to a child agent. The child agent inherits this conversation and should be able to answer: the project codeword is MARMALADE. After the subagent returns, I should reply with PARENT_DONE."},{"type":"tool-call","id":"call_00_sAtKUseRzHRBvL4CF7XF1334","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}],"usage":{"inputTokens":158,"outputTokens":147,"cacheReadTokens":2816,"reasoningTokens":59}},"sourceEventSeqs":[40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149],"surfaceOp":"append"}
+{"type":"assistant/message","seq":150,"time":1783352137159,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use subagent_fork to delegate a question to a child agent. The child agent inherits this conversation and should be able to answer: the project codeword is MARMALADE. After the subagent returns, I should reply with PARENT_DONE."},{"type":"tool-call","id":"call_00_sAtKUseRzHRBvL4CF7XF1334","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":158,"outputTokens":147,"cacheReadTokens":2816,"reasoningTokens":59}},"sourceEventSeqs":[40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149],"surfaceOp":"append"}
 {"type":"tool/call","seq":151,"time":1783352137159,"data":{"turn":2,"step":1,"callId":"call_00_sAtKUseRzHRBvL4CF7XF1334","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}}
 {"type":"tool/result","seq":152,"time":1783352138315,"data":{"turn":2,"step":1,"callId":"call_00_sAtKUseRzHRBvL4CF7XF1334","content":[{"type":"text","text":"MARMALADE"}],"isError":false},"sourceEventSeqs":[151],"surfaceOp":"append"}
 {"type":"step/end","seq":153,"time":1783352138316,"data":{"turn":2,"step":1}}
@@ -189,6 +189,6 @@
 {"type":"assistant/chunk","seq":187,"time":1783352139274,"data":{"turn":2,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"PARENT_DONE"}}}}
 {"type":"assistant/chunk","seq":188,"time":1783352139274,"data":{"turn":2,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":65,"outputTokens":30,"cacheReadTokens":3072,"reasoningTokens":25}}}}
 {"type":"assistant/chunk","seq":189,"time":1783352139274,"data":{"turn":2,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":190,"time":1783352139274,"data":{"turn":2,"step":2,"content":[{"type":"reasoning","text":"The forked child agent correctly returned \"MARMALADE\". Now I need to reply with \"PARENT_DONE\"."},{"type":"text","text":"PARENT_DONE"}],"usage":{"inputTokens":65,"outputTokens":30,"cacheReadTokens":3072,"reasoningTokens":25}},"sourceEventSeqs":[155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189],"surfaceOp":"append"}
+{"type":"assistant/message","seq":190,"time":1783352139274,"data":{"turn":2,"step":2,"content":[{"type":"reasoning","text":"The forked child agent correctly returned \"MARMALADE\". Now I need to reply with \"PARENT_DONE\"."},{"type":"text","text":"PARENT_DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":65,"outputTokens":30,"cacheReadTokens":3072,"reasoningTokens":25}},"sourceEventSeqs":[155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189],"surfaceOp":"append"}
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 {"type":"turn/end","seq":192,"time":1783352139274,"data":{"turn":2,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-mixed/session.1.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-mixed/session.1.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352145224,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352145224,"data":{"content":[{"type":"text","text":"Reply with exactly the word ALPHA and nothing else."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352145224,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352145224,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352145224,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352145820,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
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 {"type":"assistant/chunk","seq":6,"time":1783352145985,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -31,6 +31,6 @@
 {"type":"assistant/chunk","seq":29,"time":1783352146129,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"ALPHA"}}}}
 {"type":"assistant/chunk","seq":30,"time":1783352146129,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":48,"outputTokens":23,"cacheReadTokens":2816,"reasoningTokens":19}}}}
 {"type":"assistant/chunk","seq":31,"time":1783352146129,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":32,"time":1783352146130,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user asked me to reply with exactly the word \"ALPHA\" and nothing else."},{"type":"text","text":"ALPHA"}],"usage":{"inputTokens":48,"outputTokens":23,"cacheReadTokens":2816,"reasoningTokens":19}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"surfaceOp":"append"}
+{"type":"assistant/message","seq":32,"time":1783352146130,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user asked me to reply with exactly the word \"ALPHA\" and nothing else."},{"type":"text","text":"ALPHA"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":48,"outputTokens":23,"cacheReadTokens":2816,"reasoningTokens":19}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"surfaceOp":"append"}
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 {"type":"turn/end","seq":34,"time":1783352146130,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-mixed/session.2.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-mixed/session.2.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352142834,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352142834,"data":{"content":[{"type":"text","text":"Remember this fact for later: the project codeword is SAFFRON. Reply with the single word OK and stop. Do not use any tools."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352142835,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352142836,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352142836,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
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@@ -27,13 +27,13 @@
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+{"type":"assistant/message","seq":28,"time":1783352143771,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember a codeword and just reply with \"OK\"."},{"type":"text","text":"OK"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2883,"outputTokens":19,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27],"surfaceOp":"append"}
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 {"type":"step/start","seq":33,"time":1783352147509,"data":{"turn":2,"step":1}}
-{"type":"request/header","seq":34,"time":1783352147509,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"resume"}}
+{"type":"request/header","seq":34,"time":1783352147509,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"resume"}}
 {"type":"assistant/chunk","seq":35,"time":1783352147925,"data":{"turn":2,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":36,"time":1783352147925,"data":{"turn":2,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":37,"time":1783352148019,"data":{"turn":2,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -74,6 +74,6 @@
 {"type":"assistant/chunk","seq":72,"time":1783352148345,"data":{"turn":2,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"SAFFRON"}}}}
 {"type":"assistant/chunk","seq":73,"time":1783352148345,"data":{"turn":2,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":95,"outputTokens":35,"cacheReadTokens":2816,"reasoningTokens":31}}}}
 {"type":"assistant/chunk","seq":74,"time":1783352148345,"data":{"turn":2,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":75,"time":1783352148345,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user is asking me to recall the project codeword that was mentioned earlier in the conversation. I was told to remember it: SAFFRON."},{"type":"text","text":"SAFFRON"}],"usage":{"inputTokens":95,"outputTokens":35,"cacheReadTokens":2816,"reasoningTokens":31}},"sourceEventSeqs":[35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74],"surfaceOp":"append"}
+{"type":"assistant/message","seq":75,"time":1783352148345,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user is asking me to recall the project codeword that was mentioned earlier in the conversation. I was told to remember it: SAFFRON."},{"type":"text","text":"SAFFRON"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":95,"outputTokens":35,"cacheReadTokens":2816,"reasoningTokens":31}},"sourceEventSeqs":[35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74],"surfaceOp":"append"}
 {"type":"step/end","seq":76,"time":1783352148345,"data":{"turn":2,"step":1}}
 {"type":"turn/end","seq":77,"time":1783352148345,"data":{"turn":2,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-mixed/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-mixed/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352142834,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352142834,"data":{"content":[{"type":"text","text":"Remember this fact for later: the project codeword is SAFFRON. Reply with the single word OK and stop. Do not use any tools."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352142835,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352142836,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352142836,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352143493,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352143494,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352143621,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -27,7 +27,7 @@
 {"type":"assistant/chunk","seq":25,"time":1783352143768,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"OK"}}}}
 {"type":"assistant/chunk","seq":26,"time":1783352143768,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2883,"outputTokens":19,"cacheReadTokens":0,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":27,"time":1783352143768,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":28,"time":1783352143771,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember a codeword and just reply with \"OK\"."},{"type":"text","text":"OK"}],"usage":{"inputTokens":2883,"outputTokens":19,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27],"surfaceOp":"append"}
+{"type":"assistant/message","seq":28,"time":1783352143771,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to remember a codeword and just reply with \"OK\"."},{"type":"text","text":"OK"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2883,"outputTokens":19,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27],"surfaceOp":"append"}
 {"type":"step/end","seq":29,"time":1783352143771,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":30,"time":1783352143771,"data":{"turn":1,"reason":{"kind":"completed"}}}
 {"type":"turn/start","seq":31,"time":1783352143779,"data":{"turn":2,"trigger":{"kind":"message","source":{"kind":"user"}}}}
@@ -108,7 +108,7 @@
 {"type":"assistant/chunk","seq":106,"time":1783352145221,"data":{"turn":2,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_YvHr2bGomk5HhpgDTvE81896","name":"subagent","arguments":"{\"description\": \"Reply ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}}}}
 {"type":"assistant/chunk","seq":107,"time":1783352145221,"data":{"turn":2,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":185,"outputTokens":110,"cacheReadTokens":2816,"reasoningTokens":35}}}}
 {"type":"assistant/chunk","seq":108,"time":1783352145221,"data":{"turn":2,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":109,"time":1783352145221,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"Let me do these two delegations one at a time as requested.\n\nFirst, I'll use the subagent tool (fresh child) to reply with \"ALPHA\"."},{"type":"tool-call","id":"call_00_YvHr2bGomk5HhpgDTvE81896","name":"subagent","arguments":"{\"description\": \"Reply ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}],"usage":{"inputTokens":185,"outputTokens":110,"cacheReadTokens":2816,"reasoningTokens":35}},"sourceEventSeqs":[34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108],"surfaceOp":"append"}
+{"type":"assistant/message","seq":109,"time":1783352145221,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"Let me do these two delegations one at a time as requested.\n\nFirst, I'll use the subagent tool (fresh child) to reply with \"ALPHA\"."},{"type":"tool-call","id":"call_00_YvHr2bGomk5HhpgDTvE81896","name":"subagent","arguments":"{\"description\": \"Reply ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":185,"outputTokens":110,"cacheReadTokens":2816,"reasoningTokens":35}},"sourceEventSeqs":[34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108],"surfaceOp":"append"}
 {"type":"tool/call","seq":110,"time":1783352145222,"data":{"turn":2,"step":1,"callId":"call_00_YvHr2bGomk5HhpgDTvE81896","name":"subagent","arguments":"{\"description\": \"Reply ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}}
 {"type":"tool/result","seq":111,"time":1783352146133,"data":{"turn":2,"step":1,"callId":"call_00_YvHr2bGomk5HhpgDTvE81896","content":[{"type":"text","text":"ALPHA"}],"isError":false},"sourceEventSeqs":[110],"surfaceOp":"append"}
 {"type":"step/end","seq":112,"time":1783352146134,"data":{"turn":2,"step":1}}
@@ -204,7 +204,7 @@
 {"type":"assistant/chunk","seq":202,"time":1783352147502,"data":{"turn":2,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_JSr5rhREq23wSmwSkCP77184","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}}}}
 {"type":"assistant/chunk","seq":203,"time":1783352147502,"data":{"turn":2,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":54,"outputTokens":128,"cacheReadTokens":3072,"reasoningTokens":40}}}}
 {"type":"assistant/chunk","seq":204,"time":1783352147502,"data":{"turn":2,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":205,"time":1783352147503,"data":{"turn":2,"step":2,"content":[{"type":"reasoning","text":"The first subagent returned \"ALPHA\". Now I need to use the subagent_fork tool (forked child that inherits this conversation) to ask about the project codeword."},{"type":"tool-call","id":"call_00_JSr5rhREq23wSmwSkCP77184","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}],"usage":{"inputTokens":54,"outputTokens":128,"cacheReadTokens":3072,"reasoningTokens":40}},"sourceEventSeqs":[114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204],"surfaceOp":"append"}
+{"type":"assistant/message","seq":205,"time":1783352147503,"data":{"turn":2,"step":2,"content":[{"type":"reasoning","text":"The first subagent returned \"ALPHA\". Now I need to use the subagent_fork tool (forked child that inherits this conversation) to ask about the project codeword."},{"type":"tool-call","id":"call_00_JSr5rhREq23wSmwSkCP77184","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":54,"outputTokens":128,"cacheReadTokens":3072,"reasoningTokens":40}},"sourceEventSeqs":[114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204],"surfaceOp":"append"}
 {"type":"tool/call","seq":206,"time":1783352147503,"data":{"turn":2,"step":2,"callId":"call_00_JSr5rhREq23wSmwSkCP77184","name":"subagent_fork","arguments":"{\"description\": \"Recall project codeword\", \"prompt\": \"What is the project codeword mentioned earlier in this conversation? Reply with exactly that one word and nothing else.\"}"}}
 {"type":"tool/result","seq":207,"time":1783352148348,"data":{"turn":2,"step":2,"callId":"call_00_JSr5rhREq23wSmwSkCP77184","content":[{"type":"text","text":"SAFFRON"}],"isError":false},"sourceEventSeqs":[206],"surfaceOp":"append"}
 {"type":"step/end","seq":208,"time":1783352148348,"data":{"turn":2,"step":2}}
@@ -283,6 +283,6 @@
 {"type":"assistant/chunk","seq":281,"time":1783352149821,"data":{"turn":2,"step":3,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"PARENT_DONE"}}}}
 {"type":"assistant/chunk","seq":282,"time":1783352149821,"data":{"turn":2,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":69,"outputTokens":69,"cacheReadTokens":3200,"reasoningTokens":64}}}}
 {"type":"assistant/chunk","seq":283,"time":1783352149821,"data":{"turn":2,"step":3,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":284,"time":1783352149822,"data":{"turn":2,"step":3,"content":[{"type":"reasoning","text":"Both subagents returned:\n1. First (fresh child): \"ALPHA\"\n2. Second (forked child): \"SAFFRON\" - correctly inherited the conversation context where I was asked to remember the codeword \"SAFFRON\".\n\nNow I reply with \"PARENT_DONE\" as instructed."},{"type":"text","text":"PARENT_DONE"}],"usage":{"inputTokens":69,"outputTokens":69,"cacheReadTokens":3200,"reasoningTokens":64}},"sourceEventSeqs":[210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280,281,282,283],"surfaceOp":"append"}
+{"type":"assistant/message","seq":284,"time":1783352149822,"data":{"turn":2,"step":3,"content":[{"type":"reasoning","text":"Both subagents returned:\n1. First (fresh child): \"ALPHA\"\n2. Second (forked child): \"SAFFRON\" - correctly inherited the conversation context where I was asked to remember the codeword \"SAFFRON\".\n\nNow I reply with \"PARENT_DONE\" as instructed."},{"type":"text","text":"PARENT_DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":69,"outputTokens":69,"cacheReadTokens":3200,"reasoningTokens":64}},"sourceEventSeqs":[210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280,281,282,283],"surfaceOp":"append"}
 {"type":"step/end","seq":285,"time":1783352149822,"data":{"turn":2,"step":3}}
 {"type":"turn/end","seq":286,"time":1783352149822,"data":{"turn":2,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-multi/session.1.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-multi/session.1.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352127670,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352127670,"data":{"content":[{"type":"text","text":"Reply with exactly the word ALPHA and nothing else."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352127671,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352127671,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352127671,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352128125,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352128125,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352128240,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -31,6 +31,6 @@
 {"type":"assistant/chunk","seq":29,"time":1783352128365,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"ALPHA"}}}}
 {"type":"assistant/chunk","seq":30,"time":1783352128365,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":49,"outputTokens":23,"cacheReadTokens":2816,"reasoningTokens":19}}}}
 {"type":"assistant/chunk","seq":31,"time":1783352128365,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":32,"time":1783352128365,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly the word \"ALPHA\" and nothing else."},{"type":"text","text":"ALPHA"}],"usage":{"inputTokens":49,"outputTokens":23,"cacheReadTokens":2816,"reasoningTokens":19}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"surfaceOp":"append"}
+{"type":"assistant/message","seq":32,"time":1783352128365,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly the word \"ALPHA\" and nothing else."},{"type":"text","text":"ALPHA"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":49,"outputTokens":23,"cacheReadTokens":2816,"reasoningTokens":19}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"surfaceOp":"append"}
 {"type":"step/end","seq":33,"time":1783352128365,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":34,"time":1783352128366,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-multi/session.2.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-multi/session.2.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352129662,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352129662,"data":{"content":[{"type":"text","text":"Reply with exactly the word BETA and nothing else."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352129663,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352129663,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352129663,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352130236,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352130236,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352130375,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -29,6 +29,6 @@
 {"type":"assistant/chunk","seq":27,"time":1783352130527,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"BETA"}}}}
 {"type":"assistant/chunk","seq":28,"time":1783352130527,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":48,"outputTokens":21,"cacheReadTokens":2816,"reasoningTokens":18}}}}
 {"type":"assistant/chunk","seq":29,"time":1783352130527,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":30,"time":1783352130528,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly the word \"BETA\" and nothing else."},{"type":"text","text":"BETA"}],"usage":{"inputTokens":48,"outputTokens":21,"cacheReadTokens":2816,"reasoningTokens":18}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29],"surfaceOp":"append"}
+{"type":"assistant/message","seq":30,"time":1783352130528,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly the word \"BETA\" and nothing else."},{"type":"text","text":"BETA"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":48,"outputTokens":21,"cacheReadTokens":2816,"reasoningTokens":18}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29],"surfaceOp":"append"}
 {"type":"step/end","seq":31,"time":1783352130528,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":32,"time":1783352130528,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-multi/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-multi/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352126251,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352126251,"data":{"content":[{"type":"text","text":"Use the subagent tool TWICE, once at a time, to delegate two subtasks to child agents. First subtask: 'Reply with exactly the word ALPHA and nothing else.' Second subtask (after the first returns): 'Reply with exactly the word BETA and nothing else.' After both subagents return, reply with the single word PARENT_DONE and stop. Do not use the bash tool."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352126252,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352126253,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352126253,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352126729,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352126729,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352126848,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -92,7 +92,7 @@
 {"type":"assistant/chunk","seq":90,"time":1783352127665,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_7zDCCjdsQgrk5LR2bAEQ1010","name":"subagent","arguments":"{\"description\": \"Return ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}}}}
 {"type":"assistant/chunk","seq":91,"time":1783352127665,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2938,"outputTokens":124,"cacheReadTokens":0,"reasoningTokens":49}}}}
 {"type":"assistant/chunk","seq":92,"time":1783352127665,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":93,"time":1783352127668,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the subagent tool twice, sequentially (one at a time). First subagent should reply with \"ALPHA\", second with \"BETA\". After both return, I reply with \"PARENT_DONE\"."},{"type":"tool-call","id":"call_00_7zDCCjdsQgrk5LR2bAEQ1010","name":"subagent","arguments":"{\"description\": \"Return ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}],"usage":{"inputTokens":2938,"outputTokens":124,"cacheReadTokens":0,"reasoningTokens":49}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92],"surfaceOp":"append"}
+{"type":"assistant/message","seq":93,"time":1783352127668,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the subagent tool twice, sequentially (one at a time). First subagent should reply with \"ALPHA\", second with \"BETA\". After both return, I reply with \"PARENT_DONE\"."},{"type":"tool-call","id":"call_00_7zDCCjdsQgrk5LR2bAEQ1010","name":"subagent","arguments":"{\"description\": \"Return ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2938,"outputTokens":124,"cacheReadTokens":0,"reasoningTokens":49}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92],"surfaceOp":"append"}
 {"type":"tool/call","seq":94,"time":1783352127668,"data":{"turn":1,"step":1,"callId":"call_00_7zDCCjdsQgrk5LR2bAEQ1010","name":"subagent","arguments":"{\"description\": \"Return ALPHA only\", \"prompt\": \"Reply with exactly the word ALPHA and nothing else.\"}"}}
 {"type":"tool/result","seq":95,"time":1783352128371,"data":{"turn":1,"step":1,"callId":"call_00_7zDCCjdsQgrk5LR2bAEQ1010","content":[{"type":"text","text":"ALPHA"}],"isError":false},"sourceEventSeqs":[94],"surfaceOp":"append"}
 {"type":"step/end","seq":96,"time":1783352128371,"data":{"turn":1,"step":1}}
@@ -158,7 +158,7 @@
 {"type":"assistant/chunk","seq":156,"time":1783352129661,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_FudNKuJ0fchSptGy3Scw1411","name":"subagent","arguments":"{\"description\": \"Return BETA only\", \"prompt\": \"Reply with exactly the word BETA and nothing else.\"}"}}}}
 {"type":"assistant/chunk","seq":157,"time":1783352129661,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":133,"outputTokens":96,"cacheReadTokens":2944,"reasoningTokens":23}}}}
 {"type":"assistant/chunk","seq":158,"time":1783352129661,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":159,"time":1783352129661,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"First subagent returned \"ALPHA\". Now I'll call the second subagent to return \"BETA\"."},{"type":"tool-call","id":"call_00_FudNKuJ0fchSptGy3Scw1411","name":"subagent","arguments":"{\"description\": \"Return BETA only\", \"prompt\": \"Reply with exactly the word BETA and nothing else.\"}"}],"usage":{"inputTokens":133,"outputTokens":96,"cacheReadTokens":2944,"reasoningTokens":23}},"sourceEventSeqs":[98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158],"surfaceOp":"append"}
+{"type":"assistant/message","seq":159,"time":1783352129661,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"First subagent returned \"ALPHA\". Now I'll call the second subagent to return \"BETA\"."},{"type":"tool-call","id":"call_00_FudNKuJ0fchSptGy3Scw1411","name":"subagent","arguments":"{\"description\": \"Return BETA only\", \"prompt\": \"Reply with exactly the word BETA and nothing else.\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":133,"outputTokens":96,"cacheReadTokens":2944,"reasoningTokens":23}},"sourceEventSeqs":[98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158],"surfaceOp":"append"}
 {"type":"tool/call","seq":160,"time":1783352129661,"data":{"turn":1,"step":2,"callId":"call_00_FudNKuJ0fchSptGy3Scw1411","name":"subagent","arguments":"{\"description\": \"Return BETA only\", \"prompt\": \"Reply with exactly the word BETA and nothing else.\"}"}}
 {"type":"tool/result","seq":161,"time":1783352130531,"data":{"turn":1,"step":2,"callId":"call_00_FudNKuJ0fchSptGy3Scw1411","content":[{"type":"text","text":"BETA"}],"isError":false},"sourceEventSeqs":[160],"surfaceOp":"append"}
 {"type":"step/end","seq":162,"time":1783352130531,"data":{"turn":1,"step":2}}
@@ -203,6 +203,6 @@
 {"type":"assistant/chunk","seq":201,"time":1783352131242,"data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"PARENT_DONE"}}}}
 {"type":"assistant/chunk","seq":202,"time":1783352131242,"data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":115,"outputTokens":35,"cacheReadTokens":3072,"reasoningTokens":30}}}}
 {"type":"assistant/chunk","seq":203,"time":1783352131242,"data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":204,"time":1783352131243,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"Both subagents have returned: first with \"ALPHA\", second with \"BETA\". Now I should reply with \"PARENT_DONE\"."},{"type":"text","text":"PARENT_DONE"}],"usage":{"inputTokens":115,"outputTokens":35,"cacheReadTokens":3072,"reasoningTokens":30}},"sourceEventSeqs":[164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203],"surfaceOp":"append"}
+{"type":"assistant/message","seq":204,"time":1783352131243,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"Both subagents have returned: first with \"ALPHA\", second with \"BETA\". Now I should reply with \"PARENT_DONE\"."},{"type":"text","text":"PARENT_DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":115,"outputTokens":35,"cacheReadTokens":3072,"reasoningTokens":30}},"sourceEventSeqs":[164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203],"surfaceOp":"append"}
 {"type":"step/end","seq":205,"time":1783352131243,"data":{"turn":1,"step":3}}
 {"type":"turn/end","seq":206,"time":1783352131243,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-spawn/session.1.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-spawn/session.1.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352120856,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352120856,"data":{"content":[{"type":"text","text":"Reply with exactly the word CHILD_OK and nothing else."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352120856,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352120856,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352120856,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352121437,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352121438,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352121635,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -29,6 +29,6 @@
 {"type":"assistant/chunk","seq":27,"time":1783352121777,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"CHILD_OK"}}}}
 {"type":"assistant/chunk","seq":28,"time":1783352121777,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":48,"outputTokens":21,"cacheReadTokens":2816,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":29,"time":1783352121777,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":30,"time":1783352121777,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly the word CHILD_OK and nothing else."},{"type":"text","text":"CHILD_OK"}],"usage":{"inputTokens":48,"outputTokens":21,"cacheReadTokens":2816,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29],"surfaceOp":"append"}
+{"type":"assistant/message","seq":30,"time":1783352121777,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly the word CHILD_OK and nothing else."},{"type":"text","text":"CHILD_OK"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":48,"outputTokens":21,"cacheReadTokens":2816,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29],"surfaceOp":"append"}
 {"type":"step/end","seq":31,"time":1783352121778,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":32,"time":1783352121778,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/subagent-spawn/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/subagent-spawn/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352119273,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352119274,"data":{"content":[{"type":"text","text":"Use the subagent tool exactly once to delegate this subtask to a child agent: 'Reply with exactly the word CHILD_OK and nothing else.' After the subagent returns, reply with the single word PARENT_DONE and stop. Do not use the bash tool."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352119275,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352119281,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352119281,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352119925,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352119925,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352120053,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -110,7 +110,7 @@
 {"type":"assistant/chunk","seq":108,"time":1783352120851,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_gVbLWC12Qu8JheZpVRRz8749","name":"subagent","arguments":"{\"description\": \"Reply with CHILD_OK\", \"prompt\": \"Reply with exactly the word CHILD_OK and nothing else.\"}"}}}}
 {"type":"assistant/chunk","seq":109,"time":1783352120852,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2907,"outputTokens":142,"cacheReadTokens":0,"reasoningTokens":67}}}}
 {"type":"assistant/chunk","seq":110,"time":1783352120852,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":111,"time":1783352120854,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Use the subagent tool exactly once to delegate the task: \"Reply with exactly the word CHILD_OK and nothing else.\"\n2. After the subagent returns, reply with the single word PARENT_DONE and stop.\n3. Do not use the bash tool.\n\nLet me do this."},{"type":"tool-call","id":"call_00_gVbLWC12Qu8JheZpVRRz8749","name":"subagent","arguments":"{\"description\": \"Reply with CHILD_OK\", \"prompt\": \"Reply with exactly the word CHILD_OK and nothing else.\"}"}],"usage":{"inputTokens":2907,"outputTokens":142,"cacheReadTokens":0,"reasoningTokens":67}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110],"surfaceOp":"append"}
+{"type":"assistant/message","seq":111,"time":1783352120854,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Use the subagent tool exactly once to delegate the task: \"Reply with exactly the word CHILD_OK and nothing else.\"\n2. After the subagent returns, reply with the single word PARENT_DONE and stop.\n3. Do not use the bash tool.\n\nLet me do this."},{"type":"tool-call","id":"call_00_gVbLWC12Qu8JheZpVRRz8749","name":"subagent","arguments":"{\"description\": \"Reply with CHILD_OK\", \"prompt\": \"Reply with exactly the word CHILD_OK and nothing else.\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2907,"outputTokens":142,"cacheReadTokens":0,"reasoningTokens":67}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110],"surfaceOp":"append"}
 {"type":"tool/call","seq":112,"time":1783352120854,"data":{"turn":1,"step":1,"callId":"call_00_gVbLWC12Qu8JheZpVRRz8749","name":"subagent","arguments":"{\"description\": \"Reply with CHILD_OK\", \"prompt\": \"Reply with exactly the word CHILD_OK and nothing else.\"}"}}
 {"type":"tool/result","seq":113,"time":1783352121784,"data":{"turn":1,"step":1,"callId":"call_00_gVbLWC12Qu8JheZpVRRz8749","content":[{"type":"text","text":"CHILD_OK"}],"isError":false},"sourceEventSeqs":[112],"surfaceOp":"append"}
 {"type":"step/end","seq":114,"time":1783352121784,"data":{"turn":1,"step":1}}
@@ -155,6 +155,6 @@
 {"type":"assistant/chunk","seq":153,"time":1783352122731,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"PARENT_DONE"}}}}
 {"type":"assistant/chunk","seq":154,"time":1783352122732,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":120,"outputTokens":35,"cacheReadTokens":2944,"reasoningTokens":30}}}}
 {"type":"assistant/chunk","seq":155,"time":1783352122732,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":156,"time":1783352122732,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The subagent returned \"CHILD_OK\" as expected. Now I need to reply with the single word \"PARENT_DONE\" and stop."},{"type":"text","text":"PARENT_DONE"}],"usage":{"inputTokens":120,"outputTokens":35,"cacheReadTokens":2944,"reasoningTokens":30}},"sourceEventSeqs":[116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155],"surfaceOp":"append"}
+{"type":"assistant/message","seq":156,"time":1783352122732,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The subagent returned \"CHILD_OK\" as expected. Now I need to reply with the single word \"PARENT_DONE\" and stop."},{"type":"text","text":"PARENT_DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":120,"outputTokens":35,"cacheReadTokens":2944,"reasoningTokens":30}},"sourceEventSeqs":[116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155],"surfaceOp":"append"}
 {"type":"step/end","seq":157,"time":1783352122732,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":158,"time":1783352122732,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/text-turn/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/text-turn/session.jsonl
--- a/examples/acp-agent/tests/snapshots/todo-plan/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/todo-plan/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352057655,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352057655,"data":{"content":[{"type":"text","text":"Use the todo_write tool to record a plan with exactly three todos: \"read the code\" (in_progress), \"write the fix\" (pending), \"run the tests\" (pending). Send all three in one todo_write call. Then reply with the single word DONE and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352057657,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352057657,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352057657,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352058320,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352058320,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352058426,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -94,7 +94,7 @@
 {"type":"assistant/chunk","seq":92,"time":1783352059096,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_fjAnBThbDjxepBtp3hDt3264","name":"todo_write","arguments":"{\"todos\": [{\"content\": \"read the code\", \"status\": \"in_progress\"}, {\"content\": \"write the fix\", \"status\": \"pending\"}, {\"content\": \"run the tests\", \"status\": \"pending\"}]}"}}}}
 {"type":"assistant/chunk","seq":93,"time":1783352059096,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2913,"outputTokens":121,"cacheReadTokens":0,"reasoningTokens":31}}}}
 {"type":"assistant/chunk","seq":94,"time":1783352059096,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":95,"time":1783352059099,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the todo_write tool to record a plan with exactly three todos in the specified statuses, then reply with \"DONE\"."},{"type":"tool-call","id":"call_00_fjAnBThbDjxepBtp3hDt3264","name":"todo_write","arguments":"{\"todos\": [{\"content\": \"read the code\", \"status\": \"in_progress\"}, {\"content\": \"write the fix\", \"status\": \"pending\"}, {\"content\": \"run the tests\", \"status\": \"pending\"}]}"}],"usage":{"inputTokens":2913,"outputTokens":121,"cacheReadTokens":0,"reasoningTokens":31}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94],"surfaceOp":"append"}
+{"type":"assistant/message","seq":95,"time":1783352059099,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the todo_write tool to record a plan with exactly three todos in the specified statuses, then reply with \"DONE\"."},{"type":"tool-call","id":"call_00_fjAnBThbDjxepBtp3hDt3264","name":"todo_write","arguments":"{\"todos\": [{\"content\": \"read the code\", \"status\": \"in_progress\"}, {\"content\": \"write the fix\", \"status\": \"pending\"}, {\"content\": \"run the tests\", \"status\": \"pending\"}]}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2913,"outputTokens":121,"cacheReadTokens":0,"reasoningTokens":31}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94],"surfaceOp":"append"}
 {"type":"tool/call","seq":96,"time":1783352059099,"data":{"turn":1,"step":1,"callId":"call_00_fjAnBThbDjxepBtp3hDt3264","name":"todo_write","arguments":"{\"todos\": [{\"content\": \"read the code\", \"status\": \"in_progress\"}, {\"content\": \"write the fix\", \"status\": \"pending\"}, {\"content\": \"run the tests\", \"status\": \"pending\"}]}"}}
 {"type":"todo/write","seq":97,"time":1783352059100,"data":{"todos":[{"content":"read the code","status":"in_progress"},{"content":"write the fix","status":"pending"},{"content":"run the tests","status":"pending"}]}}
 {"type":"tool/result","seq":98,"time":1783352059101,"data":{"turn":1,"step":1,"callId":"call_00_fjAnBThbDjxepBtp3hDt3264","content":[{"type":"text","text":"Updated todo list: 2 pending, 1 in progress, 0 completed."}],"isError":false},"sourceEventSeqs":[96],"surfaceOp":"append"}
@@ -129,6 +129,6 @@
 {"type":"assistant/chunk","seq":127,"time":1783352059980,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":128,"time":1783352059980,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":237,"outputTokens":24,"cacheReadTokens":2816,"reasoningTokens":21}}}}
 {"type":"assistant/chunk","seq":129,"time":1783352059980,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":130,"time":1783352059981,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The todos have been written successfully. Now I just need to reply with the single word \"DONE\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":237,"outputTokens":24,"cacheReadTokens":2816,"reasoningTokens":21}},"sourceEventSeqs":[101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129],"surfaceOp":"append"}
+{"type":"assistant/message","seq":130,"time":1783352059981,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The todos have been written successfully. Now I just need to reply with the single word \"DONE\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":237,"outputTokens":24,"cacheReadTokens":2816,"reasoningTokens":21}},"sourceEventSeqs":[101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129],"surfaceOp":"append"}
 {"type":"step/end","seq":131,"time":1783352059981,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":132,"time":1783352059981,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/tool-call-turn/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/tool-call-turn/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352044771,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352044771,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: echo SNAPSHOT_OK. Then reply with the single word DONE and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352044773,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352044773,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352044773,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352045294,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352045294,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352045396,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -57,7 +57,7 @@
 {"type":"assistant/chunk","seq":55,"time":1783352045866,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_Rn2Mz1y8uZN62ukEXiNO2077","name":"bash","arguments":"{\"command\": \"echo SNAPSHOT_OK\", \"description\": \"Run echo SNAPSHOT_OK\"}"}}}}
 {"type":"assistant/chunk","seq":56,"time":1783352045866,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2879,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":57,"time":1783352045866,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":58,"time":1783352045867,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a specific bash command and then reply with DONE."},{"type":"tool-call","id":"call_00_Rn2Mz1y8uZN62ukEXiNO2077","name":"bash","arguments":"{\"command\": \"echo SNAPSHOT_OK\", \"description\": \"Run echo SNAPSHOT_OK\"}"}],"usage":{"inputTokens":2879,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57],"surfaceOp":"append"}
+{"type":"assistant/message","seq":58,"time":1783352045867,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a specific bash command and then reply with DONE."},{"type":"tool-call","id":"call_00_Rn2Mz1y8uZN62ukEXiNO2077","name":"bash","arguments":"{\"command\": \"echo SNAPSHOT_OK\", \"description\": \"Run echo SNAPSHOT_OK\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2879,"outputTokens":89,"cacheReadTokens":0,"reasoningTokens":17}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57],"surfaceOp":"append"}
 {"type":"tool/call","seq":59,"time":1783352045867,"data":{"turn":1,"step":1,"callId":"call_00_Rn2Mz1y8uZN62ukEXiNO2077","name":"bash","arguments":"{\"command\": \"echo SNAPSHOT_OK\", \"description\": \"Run echo SNAPSHOT_OK\"}"}}
 {"type":"tool/result","seq":60,"time":1783352045879,"data":{"turn":1,"step":1,"callId":"call_00_Rn2Mz1y8uZN62ukEXiNO2077","content":[{"type":"text","text":"SNAPSHOT_OK\n"}],"isError":false},"sourceEventSeqs":[59],"surfaceOp":"append"}
 {"type":"step/end","seq":61,"time":1783352045880,"data":{"turn":1,"step":1}}
@@ -95,6 +95,6 @@
 {"type":"assistant/chunk","seq":93,"time":1783352047156,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":94,"time":1783352047156,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":170,"outputTokens":28,"cacheReadTokens":2816,"reasoningTokens":25}}}}
 {"type":"assistant/chunk","seq":95,"time":1783352047156,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":96,"time":1783352047158,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command executed successfully and printed SNAPSHOT_OK. Now I need to reply with the single word DONE."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":170,"outputTokens":28,"cacheReadTokens":2816,"reasoningTokens":25}},"sourceEventSeqs":[63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95],"surfaceOp":"append"}
+{"type":"assistant/message","seq":96,"time":1783352047158,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command executed successfully and printed SNAPSHOT_OK. Now I need to reply with the single word DONE."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":170,"outputTokens":28,"cacheReadTokens":2816,"reasoningTokens":25}},"sourceEventSeqs":[63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95],"surfaceOp":"append"}
 {"type":"step/end","seq":97,"time":1783352047158,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":98,"time":1783352047158,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/workflow-run/session.1.jsonl
+++ b/examples/acp-agent/tests/snapshots/workflow-run/session.1.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783600636316,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783600636316,"data":{"content":[{"type":"text","text":"Reply with exactly the word WF_CHILD_OK and nothing else."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783600636316,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783600636317,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783600636317,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783600638073,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783600638073,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783600638173,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -31,6 +31,6 @@
 {"type":"assistant/chunk","seq":29,"time":1783600638280,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"WF_CHILD_OK"}}}}
 {"type":"assistant/chunk","seq":30,"time":1783600638280,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":17,"outputTokens":23,"cacheReadTokens":3072,"reasoningTokens":18}}}}
 {"type":"assistant/chunk","seq":31,"time":1783600638280,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":32,"time":1783600638281,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly \"WF_CHILD_OK\" and nothing else."},{"type":"text","text":"WF_CHILD_OK"}],"usage":{"inputTokens":17,"outputTokens":23,"cacheReadTokens":3072,"reasoningTokens":18}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"surfaceOp":"append"}
+{"type":"assistant/message","seq":32,"time":1783600638281,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to reply with exactly \"WF_CHILD_OK\" and nothing else."},{"type":"text","text":"WF_CHILD_OK"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":17,"outputTokens":23,"cacheReadTokens":3072,"reasoningTokens":18}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31],"surfaceOp":"append"}
 {"type":"step/end","seq":33,"time":1783600638281,"data":{"turn":1,"step":1}}
 {"type":"turn/end","seq":34,"time":1783600638281,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/workflow-run/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/workflow-run/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783600631838,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783600631838,"data":{"content":[{"type":"text","text":"Use the workflow tool exactly once, with args omitted, meta set to { \"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\" }, and this EXACT script body (copy it verbatim):\nphase('Run')\nconst reply = await agent('Reply with exactly the word WF_CHILD_OK and nothing else.')\nreturn { reply }\nAfter the workflow returns, reply with the single word WORKFLOW_DONE and stop. Do not use any other tool."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783600631839,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783600631839,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783600631839,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783600634643,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783600634643,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783600635634,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -158,7 +158,7 @@
 {"type":"assistant/chunk","seq":156,"time":1783600636246,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_dD2BLuNeJCTh2iiYC1QR3449","name":"workflow","arguments":"{\"meta\": {\"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\"}, \"script\": \"\\nphase('Run')\\nconst reply = await agent('Reply with exactly the word WF_CHILD_OK and nothing else.')\\nreturn { reply }\\n\"}"}}}}
 {"type":"assistant/chunk","seq":157,"time":1783600636246,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":3174,"outputTokens":191,"cacheReadTokens":0,"reasoningTokens":88}}}}
 {"type":"assistant/chunk","seq":158,"time":1783600636246,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":159,"time":1783600636247,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the workflow tool exactly once with specific parameters. Let me carefully follow the instructions:\n\n1. args omitted (so I don't include it)\n2. meta = { \"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\" }\n3. script = as given verbatim\n4. After it returns, reply with \"WORKFLOW_DONE\"\n\nLet me do exactly that."},{"type":"tool-call","id":"call_00_dD2BLuNeJCTh2iiYC1QR3449","name":"workflow","arguments":"{\"meta\": {\"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\"}, \"script\": \"\\nphase('Run')\\nconst reply = await agent('Reply with exactly the word WF_CHILD_OK and nothing else.')\\nreturn { reply }\\n\"}"}],"usage":{"inputTokens":3174,"outputTokens":191,"cacheReadTokens":0,"reasoningTokens":88}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158],"surfaceOp":"append"}
+{"type":"assistant/message","seq":159,"time":1783600636247,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to use the workflow tool exactly once with specific parameters. Let me carefully follow the instructions:\n\n1. args omitted (so I don't include it)\n2. meta = { \"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\" }\n3. script = as given verbatim\n4. After it returns, reply with \"WORKFLOW_DONE\"\n\nLet me do exactly that."},{"type":"tool-call","id":"call_00_dD2BLuNeJCTh2iiYC1QR3449","name":"workflow","arguments":"{\"meta\": {\"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\"}, \"script\": \"\\nphase('Run')\\nconst reply = await agent('Reply with exactly the word WF_CHILD_OK and nothing else.')\\nreturn { reply }\\n\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":3174,"outputTokens":191,"cacheReadTokens":0,"reasoningTokens":88}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158],"surfaceOp":"append"}
 {"type":"tool/call","seq":160,"time":1783600636247,"data":{"turn":1,"step":1,"callId":"call_00_dD2BLuNeJCTh2iiYC1QR3449","name":"workflow","arguments":"{\"meta\": {\"name\": \"snapshot-flow\", \"description\": \"one child for the snapshot\"}, \"script\": \"\\nphase('Run')\\nconst reply = await agent('Reply with exactly the word WF_CHILD_OK and nothing else.')\\nreturn { reply }\\n\"}"}}
 {"type":"tool/result","seq":161,"time":1783600638304,"data":{"turn":1,"step":1,"callId":"call_00_dD2BLuNeJCTh2iiYC1QR3449","content":[{"type":"text","text":"workflow \"snapshot-flow\" completed (1 agent).\nReturn value:\n{\n  \"reply\": \"WF_CHILD_OK\"\n}"}],"isError":false},"sourceEventSeqs":[160],"surfaceOp":"append"}
 {"type":"step/end","seq":162,"time":1783600638304,"data":{"turn":1,"step":1}}
@@ -204,6 +204,6 @@
 {"type":"assistant/chunk","seq":202,"time":1783600640865,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"WORKFLOW_DONE"}}}}
 {"type":"assistant/chunk","seq":203,"time":1783600640865,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":328,"outputTokens":36,"cacheReadTokens":3072,"reasoningTokens":30}}}}
 {"type":"assistant/chunk","seq":204,"time":1783600640865,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":205,"time":1783600640865,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The workflow returned successfully with the reply \"WF_CHILD_OK\". Now I need to reply with exactly \"WORKFLOW_DONE\" and stop."},{"type":"text","text":"WORKFLOW_DONE"}],"usage":{"inputTokens":328,"outputTokens":36,"cacheReadTokens":3072,"reasoningTokens":30}},"sourceEventSeqs":[164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204],"surfaceOp":"append"}
+{"type":"assistant/message","seq":205,"time":1783600640865,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The workflow returned successfully with the reply \"WF_CHILD_OK\". Now I need to reply with exactly \"WORKFLOW_DONE\" and stop."},{"type":"text","text":"WORKFLOW_DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":328,"outputTokens":36,"cacheReadTokens":3072,"reasoningTokens":30}},"sourceEventSeqs":[164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204],"surfaceOp":"append"}
 {"type":"step/end","seq":206,"time":1783600640865,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":207,"time":1783600640865,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/acp-agent/tests/snapshots/workspace-edit/session.jsonl
+++ b/examples/acp-agent/tests/snapshots/workspace-edit/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783352264080,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783352264081,"data":{"content":[{"type":"text","text":"A file named greeting.txt in the current directory contains one word. Use the bash tool to append a second line containing the word WORLD to it (so it has two lines), then read the file back with `cat greeting.txt` to confirm, and reply with the single word DONE. Use a single bash call per action."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783352264082,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783352264083,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783352264083,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783352264544,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783352264544,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783352264642,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -77,7 +77,7 @@
 {"type":"assistant/chunk","seq":75,"time":1783352265489,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_OjRFB4zvxu6UALDjytZD0978","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}}}}
 {"type":"assistant/chunk","seq":76,"time":1783352265489,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":2918,"outputTokens":101,"cacheReadTokens":0,"reasoningTokens":55}}}}
 {"type":"assistant/chunk","seq":77,"time":1783352265489,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":78,"time":1783352265491,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Read the file greeting.txt\n2. Append the word WORLD as a second line\n3. Read the file back with cat to confirm\n4. Reply with DONE\n\nLet me start by reading the file to see its contents."},{"type":"tool-call","id":"call_00_OjRFB4zvxu6UALDjytZD0978","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}],"usage":{"inputTokens":2918,"outputTokens":101,"cacheReadTokens":0,"reasoningTokens":55}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77],"surfaceOp":"append"}
+{"type":"assistant/message","seq":78,"time":1783352265491,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to:\n1. Read the file greeting.txt\n2. Append the word WORLD as a second line\n3. Read the file back with cat to confirm\n4. Reply with DONE\n\nLet me start by reading the file to see its contents."},{"type":"tool-call","id":"call_00_OjRFB4zvxu6UALDjytZD0978","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":2918,"outputTokens":101,"cacheReadTokens":0,"reasoningTokens":55}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77],"surfaceOp":"append"}
 {"type":"tool/call","seq":79,"time":1783352265491,"data":{"turn":1,"step":1,"callId":"call_00_OjRFB4zvxu6UALDjytZD0978","name":"read","arguments":"{\"file_path\": \"greeting.txt\"}"}}
 {"type":"tool/result","seq":80,"time":1783352265504,"data":{"turn":1,"step":1,"callId":"call_00_OjRFB4zvxu6UALDjytZD0978","content":[{"type":"text","text":"<path>/tmp/acp-snap-cwd-rxbEpP/greeting.txt</path>\n<type>file</type>\n<content>\n1: hello\n\n(End of file - total 1 lines)\n</content>"}],"isError":false},"sourceEventSeqs":[79],"surfaceOp":"append"}
 {"type":"step/end","seq":81,"time":1783352265504,"data":{"turn":1,"step":1}}
@@ -154,7 +154,7 @@
 {"type":"assistant/chunk","seq":152,"time":1783352267302,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_IUUvbNiPcnwhVL8ErEFS4806","name":"bash","arguments":"{\"command\": \"printf '\\\\nWORLD' >> greeting.txt\", \"description\": \"Append newline and WORLD to greeting.txt\"}"}}}}
 {"type":"assistant/chunk","seq":153,"time":1783352267302,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":261,"outputTokens":107,"cacheReadTokens":2816,"reasoningTokens":32}}}}
 {"type":"assistant/chunk","seq":154,"time":1783352267302,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":155,"time":1783352267302,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The file contains \"hello\" on one line. Now I need to append a second line with \"WORLD\" to it. Then cat it to confirm."},{"type":"tool-call","id":"call_00_IUUvbNiPcnwhVL8ErEFS4806","name":"bash","arguments":"{\"command\": \"printf '\\\\nWORLD' >> greeting.txt\", \"description\": \"Append newline and WORLD to greeting.txt\"}"}],"usage":{"inputTokens":261,"outputTokens":107,"cacheReadTokens":2816,"reasoningTokens":32}},"sourceEventSeqs":[83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154],"surfaceOp":"append"}
+{"type":"assistant/message","seq":155,"time":1783352267302,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The file contains \"hello\" on one line. Now I need to append a second line with \"WORLD\" to it. Then cat it to confirm."},{"type":"tool-call","id":"call_00_IUUvbNiPcnwhVL8ErEFS4806","name":"bash","arguments":"{\"command\": \"printf '\\\\nWORLD' >> greeting.txt\", \"description\": \"Append newline and WORLD to greeting.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":261,"outputTokens":107,"cacheReadTokens":2816,"reasoningTokens":32}},"sourceEventSeqs":[83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154],"surfaceOp":"append"}
 {"type":"tool/call","seq":156,"time":1783352267302,"data":{"turn":1,"step":2,"callId":"call_00_IUUvbNiPcnwhVL8ErEFS4806","name":"bash","arguments":"{\"command\": \"printf '\\\\nWORLD' >> greeting.txt\", \"description\": \"Append newline and WORLD to greeting.txt\"}"}}
 {"type":"tool/result","seq":157,"time":1783352267330,"data":{"turn":1,"step":2,"callId":"call_00_IUUvbNiPcnwhVL8ErEFS4806","content":[{"type":"text","text":"(no output)"}],"isError":false},"sourceEventSeqs":[156],"surfaceOp":"append"}
 {"type":"step/end","seq":158,"time":1783352267330,"data":{"turn":1,"step":2}}
@@ -201,7 +201,7 @@
 {"type":"assistant/chunk","seq":199,"time":1783352268414,"data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_Wo4H7tFNheZJWKVDrAHK5851","name":"bash","arguments":"{\"command\": \"cat greeting.txt\", \"description\": \"Read greeting.txt to confirm\"}"}}}}
 {"type":"assistant/chunk","seq":200,"time":1783352268414,"data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":126,"outputTokens":77,"cacheReadTokens":3072,"reasoningTokens":12}}}}
 {"type":"assistant/chunk","seq":201,"time":1783352268414,"data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":202,"time":1783352268415,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"Good, now let me read the file back with cat."},{"type":"tool-call","id":"call_00_Wo4H7tFNheZJWKVDrAHK5851","name":"bash","arguments":"{\"command\": \"cat greeting.txt\", \"description\": \"Read greeting.txt to confirm\"}"}],"usage":{"inputTokens":126,"outputTokens":77,"cacheReadTokens":3072,"reasoningTokens":12}},"sourceEventSeqs":[160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201],"surfaceOp":"append"}
+{"type":"assistant/message","seq":202,"time":1783352268415,"data":{"turn":1,"step":3,"content":[{"type":"reasoning","text":"Good, now let me read the file back with cat."},{"type":"tool-call","id":"call_00_Wo4H7tFNheZJWKVDrAHK5851","name":"bash","arguments":"{\"command\": \"cat greeting.txt\", \"description\": \"Read greeting.txt to confirm\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":126,"outputTokens":77,"cacheReadTokens":3072,"reasoningTokens":12}},"sourceEventSeqs":[160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201],"surfaceOp":"append"}
 {"type":"tool/call","seq":203,"time":1783352268415,"data":{"turn":1,"step":3,"callId":"call_00_Wo4H7tFNheZJWKVDrAHK5851","name":"bash","arguments":"{\"command\": \"cat greeting.txt\", \"description\": \"Read greeting.txt to confirm\"}"}}
 {"type":"tool/result","seq":204,"time":1783352268429,"data":{"turn":1,"step":3,"callId":"call_00_Wo4H7tFNheZJWKVDrAHK5851","content":[{"type":"text","text":"hello\n\nWORLD"}],"isError":false},"sourceEventSeqs":[203],"surfaceOp":"append"}
 {"type":"step/end","seq":205,"time":1783352268429,"data":{"turn":1,"step":3}}
@@ -236,6 +236,6 @@
 {"type":"assistant/chunk","seq":234,"time":1783352269538,"data":{"turn":1,"step":4,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":235,"time":1783352269538,"data":{"turn":1,"step":4,"chunk":{"type":"usage","usage":{"inputTokens":219,"outputTokens":25,"cacheReadTokens":3072,"reasoningTokens":22}}}}
 {"type":"assistant/chunk","seq":236,"time":1783352269538,"data":{"turn":1,"step":4,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":237,"time":1783352269538,"data":{"turn":1,"step":4,"content":[{"type":"reasoning","text":"The file now has two lines:\n1. hello\n2. WORLD\n\nI can reply with DONE."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":219,"outputTokens":25,"cacheReadTokens":3072,"reasoningTokens":22}},"sourceEventSeqs":[207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236],"surfaceOp":"append"}
+{"type":"assistant/message","seq":237,"time":1783352269538,"data":{"turn":1,"step":4,"content":[{"type":"reasoning","text":"The file now has two lines:\n1. hello\n2. WORLD\n\nI can reply with DONE."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":219,"outputTokens":25,"cacheReadTokens":3072,"reasoningTokens":22}},"sourceEventSeqs":[207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236],"surfaceOp":"append"}
 {"type":"step/end","seq":238,"time":1783352269538,"data":{"turn":1,"step":4}}
 {"type":"turn/end","seq":239,"time":1783352269539,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/coding-agent/code-mode.cordis.yml
+++ b/examples/coding-agent/code-mode.cordis.yml
@@ -16,6 +16,7 @@
      - id: stdio-agent
        name: '@deepseek-ai/dsh-stdio-agent'
        config:
+          provider: deepseek
          model: deepseek-v4-flash
          resumeSessionId: !!js process.env.RESUME_SESSION_ID
          persistenceRoot: './.sessions'
--- a/examples/coding-agent/cordis.yml
+++ b/examples/coding-agent/cordis.yml
@@ -17,16 +17,12 @@
  config:
    root: ['.']

-# The DeepSeek adapter. Swap to '@deepseek-ai/dsh-llm-pi-ai' for the pi-ai-backed
-# twin (same config shape; `reasoning: high` replaces thinking/reasoningEffort).
+# The native DeepSeek adapter.
 - id: llm-deepseek
  name: '@deepseek-ai/dsh-llm-deepseek'
  config:
    apiKey: !!js process.env.DEEPSEEK_API_KEY
    baseURL: !!js process.env.DEEPSEEK_BASE_URL
-    models:
-      - deepseek-v4-pro
-      - deepseek-v4-flash

 # Local bash executor for agent-core's tool-bash schema (one of several tool
 # stacks in this tree: filesystem, subagent, and todo_write load below).
@@ -40,6 +36,7 @@
 - id: stdio-agent
  name: '@deepseek-ai/dsh-stdio-agent'
  config:
+    provider: deepseek
    model: deepseek-v4-flash
    # Set RESUME_SESSION_ID to continue a prior persisted session (the ids live
    # under ./.sessions); unset starts a fresh session each run.
@@ -66,6 +63,7 @@
    contextWindow: 128000
    thresholdRatio: 0.8
    retainTokens: 20480
+    summarizationProvider: ''
    summarizationModel: ''
    maxTokens: 8192
    compactionRetries: 1
--- a/examples/coding-agent/tests/code-mode.e2e.ts
+++ b/examples/coding-agent/tests/code-mode.e2e.ts
@@ -50,7 +50,7 @@ async function codeModeHarness(cwd: string): Promise<Context> {
  await harness.plugin(ToolRegistry, { mode: 'code' })
  await harness.plugin(AgentRegistry)
  await harness.plugin(AgentLoop, { agents: [] })
-  await harness.plugin(LlmDeepSeek, { models: ['deepseek-v4-flash'] })
+  await harness.plugin(LlmDeepSeek)
  await harness.plugin(LocalBashExecutor, { cwd, timeoutMs: 30_000 })
  await harness.plugin(ToolBash)
  await harness.plugin(WorkerCodeRuntime, {})
@@ -72,7 +72,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('Code Mode: real model writes a p
  it('collapses the wire tool list to [run_code], bridges sub-calls, and returns curated output', async () => {
    workdir = await mkdtemp(join(tmpdir(), 'dsh-code-mode-e2e-'))
    ctx = await codeModeHarness(workdir)
-    const agent = ctx.agentLoop.create(AgentId('e2e-code-mode'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('e2e-code-mode'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{
      type: 'text',
--- a/examples/coding-agent/tests/coding-task.e2e.ts
+++ b/examples/coding-agent/tests/coding-task.e2e.ts
@@ -54,7 +54,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('coding task: fix a failing test
    expect(before.status).not.toBe(0)

    ctx = await codingHarness(workdir, { persona: SYSTEM_PROMPT })
-    const agent = ctx.agentLoop.create(AgentId('e2e-task'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('e2e-task'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{
      type: 'text',
--- a/examples/coding-agent/tests/compaction.e2e.ts
+++ b/examples/coding-agent/tests/compaction.e2e.ts
@@ -58,13 +58,14 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('compaction: a long session compa
        contextWindow: 2000,
        thresholdRatio: 0.5,
        retainTokens: 400,
+        summarizationProvider: '',
        summarizationModel: '',
        maxTokens: 1024,
        compactionRetries: 1,
      },
      persistenceRoot: join(workdir, '.sessions'),
    })
-    const agent = ctx.agentLoop.create(AgentId('e2e-compaction'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('e2e-compaction'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{
      type: 'text',
--- a/examples/coding-agent/tests/full-loop.e2e.ts
+++ b/examples/coding-agent/tests/full-loop.e2e.ts
@@ -28,7 +28,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('full loop: real model + real bas
  it('runs a bash command on request and reports its output', async () => {
    workdir = await mkdtemp(join(tmpdir(), 'dsh-full-loop-e2e-'))
    ctx = await codingHarness(workdir, { persona: SYSTEM_PROMPT })
-    const agent = ctx.agentLoop.create(AgentId('e2e-loop'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('e2e-loop'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{ type: 'text', text: 'Run `echo e2e-ok` with the bash tool and tell me its exact output.' }])
    await waitForIdle(ctx, agent)
--- a/examples/coding-agent/tests/harness.ts
+++ b/examples/coding-agent/tests/harness.ts
@@ -56,7 +56,7 @@ export async function codingHarness(workdir: string, options: CodingHarnessOptio
  await ctx.plugin(ToolRegistry)
  await ctx.plugin(AgentRegistry)
  await ctx.plugin(AgentLoop, { agents: [] })
-  await ctx.plugin(LlmDeepSeek, { models: ['deepseek-v4-flash'] })
+  await ctx.plugin(LlmDeepSeek)
  await ctx.plugin(LocalBashExecutor, { cwd: workdir, timeoutMs: 30_000 })
  await ctx.plugin(ToolBash)
  await ctx.plugin(ToolTodo)
--- a/examples/coding-agent/tests/resume.e2e.ts
+++ b/examples/coding-agent/tests/resume.e2e.ts
@@ -42,7 +42,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('resume: continue a persisted ses
    const first = (await ctx.agents.create({
      agentId: AgentId('resume-1'),
      sessionId: SESSION_ID,
-      agentOptions: { model: 'deepseek-v4-flash' },
+      agentOptions: { provider: 'deepseek', model: 'deepseek-v4-flash' },
    })).agent as ReactLoopAgent
    first.send([{ type: 'text', text: `Remember this code for later: ${SECRET}. Just acknowledge it.` }])
    await waitForIdle(ctx, first)
@@ -56,7 +56,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('resume: continue a persisted ses
    const resumed = (await ctx.agents.resume({
      agentId: AgentId('resume-2'),
      resumeSessionId: SESSION_ID,
-      agentOptions: { model: 'deepseek-v4-flash' },
+      agentOptions: { provider: 'deepseek', model: 'deepseek-v4-flash' },
    })).agent as ReactLoopAgent
    expect(resumed.session.id).toBe(SESSION_ID)
    // The prior user turn is in the rehydrated log before the model is asked.
--- a/examples/coding-agent/tests/todo-write.e2e.ts
+++ b/examples/coding-agent/tests/todo-write.e2e.ts
@@ -26,7 +26,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('todo_write: real model records a
  it('appends a todo/write event with the model-produced task list', async () => {
    workdir = await mkdtemp(join(tmpdir(), 'dsh-todo-write-e2e-'))
    ctx = await codingHarness(workdir, { persona: TODO_SYSTEM_PROMPT })
-    const agent = ctx.agentLoop.create(AgentId('e2e-todo'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('e2e-todo'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{ type: 'text', text:
      'Use the todo_write tool to record a plan of exactly two steps: first '
--- a/examples/cordis-agent/cordis.yml
+++ b/examples/cordis-agent/cordis.yml
@@ -25,9 +25,6 @@
  config:
    apiKey: !!js process.env.DEEPSEEK_API_KEY
    baseURL: !!js process.env.DEEPSEEK_BASE_URL
-    models:
-      - deepseek-v4-pro
-      - deepseek-v4-flash

 # Local bash executor for agent-core's tool-bash schema — gives the agent an
 # ordinary tool whose calls make the mounted listeners observably fire.
@@ -58,6 +55,7 @@
 - id: stdio-agent
  name: '@deepseek-ai/dsh-stdio-agent'
  config:
+    provider: deepseek
    model: deepseek-v4-flash
    resumeSessionId: !!js process.env.RESUME_SESSION_ID
    persistenceRoot: './.sessions'
--- a/examples/cordis-agent/tests/cordis-tools.e2e.ts
+++ b/examples/cordis-agent/tests/cordis-tools.e2e.ts
@@ -38,7 +38,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('cordis tools: a real model modif
  it('mounts a status listener whose tagged output actually fires, then unmounts it', async () => {
    ctx = await cordisHarness()
    const log = vi.spyOn(console, 'log').mockImplementation(() => {})
-    const agent = ctx.agentLoop.create(AgentId('cordis-e2e-listener'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('cordis-e2e-listener'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{
      type: 'text',
@@ -66,7 +66,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('cordis tools: a real model modif

  it('builds itself a reverse_text tool and actually calls it', async () => {
    ctx = await cordisHarness()
-    const agent = ctx.agentLoop.create(AgentId('cordis-e2e-selftool'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('cordis-e2e-selftool'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{
      type: 'text',
@@ -114,7 +114,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY)('cordis tools: a real model modif

  it('composes two mounts through provide/inject, and unmounting the provider parks the consumer', async () => {
    ctx = await cordisHarness()
-    const agent = ctx.agentLoop.create(AgentId('cordis-e2e-compose'), { model: 'deepseek-v4-flash' })
+    const agent = ctx.agentLoop.create(AgentId('cordis-e2e-compose'), { provider: 'deepseek', model: 'deepseek-v4-flash' })

    agent.send([{
      type: 'text',
--- a/examples/cordis-agent/tests/harness.ts
+++ b/examples/cordis-agent/tests/harness.ts
@@ -29,7 +29,7 @@ export async function cordisHarness(): Promise<Context> {
  await ctx.plugin(ToolRegistry)
  await ctx.plugin(AgentRegistry)
  await ctx.plugin(AgentLoop, { agents: [] })
-  await ctx.plugin(LlmDeepSeek, { models: ['deepseek-v4-flash'] })
+  await ctx.plugin(LlmDeepSeek)
  await ctx.plugin(ToolCordis)
  return ctx
 }
--- a/examples/echo-agent/cordis.yml
+++ b/examples/echo-agent/cordis.yml
@@ -32,6 +32,7 @@
 - id: stdio-agent
  name: '@deepseek-ai/dsh-stdio-agent'
  config:
+    provider: mock
    model: mock-echo
    persona: 'You are echo-agent, a demo agent.'
    welcome: 'echo-agent ready. Type a message ("echo <text>" triggers the tool).'
--- a/examples/echo-agent/src/mock-llm.ts
+++ b/examples/echo-agent/src/mock-llm.ts
@@ -55,5 +55,5 @@ export const name = 'mock-llm'
 export const inject = ['llm']

 export function apply(ctx: Context) {
-  ctx.llm.registerAdapter(['mock-echo'], new MockEchoAdapter())
+  ctx.llm.registerAdapter(['mock'], new MockEchoAdapter())
 }
--- a/examples/sandbox-acp-agent/cordis.yml
+++ b/examples/sandbox-acp-agent/cordis.yml
@@ -18,8 +18,6 @@
  config:
    apiKey: !!js process.env.DEEPSEEK_API_KEY
    baseURL: !!js process.env.DEEPSEEK_BASE_URL
-    models:
-      - deepseek-v4-flash

 # The sandbox stack: the platform-runner provider (bwrap → per-platform
 # Landlock launcher → Seatbelt, functionally probed), then the confined bash executor.
@@ -49,6 +47,7 @@
 - id: acp-agent
  name: '@deepseek-ai/dsh-acp-agent'
  config:
+    provider: deepseek
    model: deepseek-v4-flash
    # Persistence root: $DSH_SNAPSHOT_SESSIONS_ROOT when the snapshot harness
    # sets it (so a record run's logs land where the harness harvests them),
--- a/examples/sandbox-acp-agent/tests/snapshots/escalation-approved/session.jsonl
+++ b/examples/sandbox-acp-agent/tests/snapshots/escalation-approved/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783486769426,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783486769426,"data":{"content":[{"type":"text","text":"The sandbox already denied writing escalated.txt in this workspace earlier. Retry it now exactly once: one single bash call with the command printf 'escalated\\n' > escalated.txt && cat escalated.txt, with sandbox_permissions set to workspace-write and the justification 'the user asked to write escalated.txt in the workspace'. Do not run it without sandbox_permissions first. I will approve the permission prompt. After the result, reply with the single word DONE and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783486769427,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783486769427,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783486769427,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783486770051,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783486770052,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783486770179,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -112,7 +112,7 @@
 {"type":"assistant/chunk","seq":110,"time":1783486771232,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_ZSEIrZNdgQhL2QJgVHww8689","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt and cat its content\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}}}}
 {"type":"assistant/chunk","seq":111,"time":1783486771232,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":1255,"outputTokens":160,"cacheReadTokens":0,"reasoningTokens":34}}}}
 {"type":"assistant/chunk","seq":112,"time":1783486771232,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":113,"time":1783486771236,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to retry the command with sandbox_permissions set to workspace-write. They explicitly said they will approve the permission prompt. Let me proceed."},{"type":"tool-call","id":"call_00_ZSEIrZNdgQhL2QJgVHww8689","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt and cat its content\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}],"usage":{"inputTokens":1255,"outputTokens":160,"cacheReadTokens":0,"reasoningTokens":34}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112],"surfaceOp":"append"}
+{"type":"assistant/message","seq":113,"time":1783486771236,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to retry the command with sandbox_permissions set to workspace-write. They explicitly said they will approve the permission prompt. Let me proceed."},{"type":"tool-call","id":"call_00_ZSEIrZNdgQhL2QJgVHww8689","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt and cat its content\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":1255,"outputTokens":160,"cacheReadTokens":0,"reasoningTokens":34}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112],"surfaceOp":"append"}
 {"type":"tool/call","seq":114,"time":1783486771236,"data":{"turn":1,"step":1,"callId":"call_00_ZSEIrZNdgQhL2QJgVHww8689","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt and cat its content\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}}
 {"type":"approval/asked","seq":115,"time":1783486771238,"data":{"id":"3ec45405-5add-4929-a755-e8c077ec7a7e","toolName":"bash","callId":"call_00_ZSEIrZNdgQhL2QJgVHww8689","reason":"escalate sandbox to workspace-write: the user asked to write escalated.txt in the workspace"}}
 {"type":"approval/decided","seq":116,"time":1783486771243,"data":{"id":"3ec45405-5add-4929-a755-e8c077ec7a7e","outcome":"allowed-once"}}
@@ -144,6 +144,6 @@
 {"type":"assistant/chunk","seq":142,"time":1783486772229,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":143,"time":1783486772229,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":23,"outputTokens":20,"cacheReadTokens":1408,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":144,"time":1783486772229,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":145,"time":1783486772230,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command succeeded. The user asked me to reply with the single word DONE."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":23,"outputTokens":20,"cacheReadTokens":1408,"reasoningTokens":17}},"sourceEventSeqs":[120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144],"surfaceOp":"append"}
+{"type":"assistant/message","seq":145,"time":1783486772230,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command succeeded. The user asked me to reply with the single word DONE."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":23,"outputTokens":20,"cacheReadTokens":1408,"reasoningTokens":17}},"sourceEventSeqs":[120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144],"surfaceOp":"append"}
 {"type":"step/end","seq":146,"time":1783486772230,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":147,"time":1783486772230,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/sandbox-acp-agent/tests/snapshots/escalation-rejected/session.jsonl
+++ b/examples/sandbox-acp-agent/tests/snapshots/escalation-rejected/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783486772551,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783486772551,"data":{"content":[{"type":"text","text":"The sandbox already denied writing escalated.txt in this workspace earlier. Retry it now exactly once: one single bash call with the command printf 'escalated\\n' > escalated.txt && cat escalated.txt, with sandbox_permissions set to workspace-write and the justification 'the user asked to write escalated.txt in the workspace'. Do not run it without sandbox_permissions first. I will reject the permission prompt; after the rejection, do not retry and do not work around it — explain in one short sentence that the escalation was rejected, then stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783486772552,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783486772552,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783486772552,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":"{{tools}}"},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783486773136,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783486773136,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783486773275,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -149,7 +149,7 @@
 {"type":"assistant/chunk","seq":147,"time":1783486774569,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_ODln9LCQtuvTw4FDZEfe3479","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt with workspace-write permission\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}}}}
 {"type":"assistant/chunk","seq":148,"time":1783486774569,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":1269,"outputTokens":197,"cacheReadTokens":0,"reasoningTokens":70}}}}
 {"type":"assistant/chunk","seq":149,"time":1783486774569,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":150,"time":1783486774572,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to retry the exact command `printf 'escalated\\n' > escalated.txt && cat escalated.txt` with `sandbox_permissions` set to `workspace-write` and the justification they specified. They explicitly say they will reject the permission prompt, so after rejection I should explain in one short sentence and stop."},{"type":"tool-call","id":"call_00_ODln9LCQtuvTw4FDZEfe3479","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt with workspace-write permission\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}],"usage":{"inputTokens":1269,"outputTokens":197,"cacheReadTokens":0,"reasoningTokens":70}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149],"surfaceOp":"append"}
+{"type":"assistant/message","seq":150,"time":1783486774572,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to retry the exact command `printf 'escalated\\n' > escalated.txt && cat escalated.txt` with `sandbox_permissions` set to `workspace-write` and the justification they specified. They explicitly say they will reject the permission prompt, so after rejection I should explain in one short sentence and stop."},{"type":"tool-call","id":"call_00_ODln9LCQtuvTw4FDZEfe3479","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt with workspace-write permission\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":1269,"outputTokens":197,"cacheReadTokens":0,"reasoningTokens":70}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149],"surfaceOp":"append"}
 {"type":"tool/call","seq":151,"time":1783486774572,"data":{"turn":1,"step":1,"callId":"call_00_ODln9LCQtuvTw4FDZEfe3479","name":"bash","arguments":"{\"command\": \"printf 'escalated\\\\n' > escalated.txt && cat escalated.txt\", \"description\": \"Write escalated.txt with workspace-write permission\", \"sandbox_permissions\": \"workspace-write\", \"justification\": \"the user asked to write escalated.txt in the workspace\"}"}}
 {"type":"approval/asked","seq":152,"time":1783486774574,"data":{"id":"ed977255-38a3-4c1d-9f4e-0e258ef86e94","toolName":"bash","callId":"call_00_ODln9LCQtuvTw4FDZEfe3479","reason":"escalate sandbox to workspace-write: the user asked to write escalated.txt in the workspace"}}
 {"type":"approval/decided","seq":153,"time":1783486774578,"data":{"id":"ed977255-38a3-4c1d-9f4e-0e258ef86e94","outcome":"rejected"}}
@@ -197,6 +197,6 @@
 {"type":"assistant/chunk","seq":195,"time":1783486776185,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"The escalation request to write to the workspace was rejected, so the command was not executed."}}}}
 {"type":"assistant/chunk","seq":196,"time":1783486776185,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":341,"outputTokens":36,"cacheReadTokens":1152,"reasoningTokens":17}}}}
 {"type":"assistant/chunk","seq":197,"time":1783486776185,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":198,"time":1783486776186,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user rejected the escalation. I need to explain in one short sentence and stop."},{"type":"text","text":"The escalation request to write to the workspace was rejected, so the command was not executed."}],"usage":{"inputTokens":341,"outputTokens":36,"cacheReadTokens":1152,"reasoningTokens":17}},"sourceEventSeqs":[157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197],"surfaceOp":"append"}
+{"type":"assistant/message","seq":198,"time":1783486776186,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The user rejected the escalation. I need to explain in one short sentence and stop."},{"type":"text","text":"The escalation request to write to the workspace was rejected, so the command was not executed."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":341,"outputTokens":36,"cacheReadTokens":1152,"reasoningTokens":17}},"sourceEventSeqs":[157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197],"surfaceOp":"append"}
 {"type":"step/end","seq":199,"time":1783486776186,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":200,"time":1783486776186,"data":{"turn":1,"reason":{"kind":"completed"}}}
--- a/examples/sandbox-acp-agent/tests/snapshots/mode-switching/session.jsonl
+++ b/examples/sandbox-acp-agent/tests/snapshots/mode-switching/session.jsonl
@@ -2,7 +2,7 @@
 {"type":"turn/start","seq":0,"time":1783613224997,"data":{"turn":1,"trigger":{"kind":"message","source":{"kind":"user"}}}}
 {"type":"user/message","seq":1,"time":1783613224997,"data":{"content":[{"type":"text","text":"Use the bash tool to run exactly: cat notes.txt. Then reply with the single word DONE and stop."}],"source":{"kind":"user"}},"surfaceOp":"append"}
 {"type":"step/start","seq":2,"time":1783613224997,"data":{"turn":1,"step":1}}
-{"type":"request/header","seq":3,"time":1783613224997,"data":{"header":{"config":{"model":"deepseek-v4-flash"},"system":"{{system}}","tools":[{"name":"bash","description":"Execute a bash command (`bash -c`) and return its stdout/stderr. Each call runs in a fresh shell: no state (cwd, variables, functions) persists between calls — pass `workdir` instead of using `cd`. Non-zero exits are reported as `[exit code: N]`. Commands may run under a file sandbox; a blocked file operation is reported as `[sandbox: file access denied under <mode> mode]` — a policy denial, not a bug in the command; do not retry another way (a background task reports the same marker via bash_output once it has finished). Long output is truncated to its tail; the full output is saved to a file whose path is reported when available. Set `run_in_background: true` for long-running commands: the call returns a task id immediately; poll it with `bash_output` and stop it with `bash_kill`. Attempting a command the sandbox may deny is safe and expected: run it and read the marker rather than assuming the denial. When a command IS denied and a wider mode would let it succeed, escalate immediately in the SAME turn — the ONE sanctioned exception to a denial: retry the exact same command once with `sandbox_permissions` (the narrowest wider mode that suffices) plus a one-sentence `justification`. Do not detour through chat to ask permission first — the approval prompt raised by that retry IS how the user consents. If the session states approval prompts are disabled, there is no exception: a denial is final — do not set `sandbox_permissions`. Never escalate speculatively: ground the request in a real denial — normally the one THIS command just hit; escalating up front is fine only when this session already denied the same access. A rejected escalation is final for THAT command — stop and explain, never work around it — but it does not forbid attempting or escalating other commands later.","parameters":{"type":"object","properties":{"command":{"type":"string","description":"The bash command to execute."},"description":{"type":"string","description":"Clear, concise description of what this command does in active voice, 5-10 words (shown in the UI). Examples: \"ls\" → \"List files in current directory\"; \"git status\" → \"Show working tree status\"; \"npm install\" → \"Install package dependencies\"."},"timeoutMs":{"type":"number","description":"Timeout in milliseconds. The executor applies its configured default and cap, and kills the command on expiry."},"workdir":{"type":"string","description":"Working directory for this command. Defaults to the session workspace; a relative path is resolved against it."},"run_in_background":{"type":"boolean","description":"Run in the background and return a task id immediately. No timeout applies."},"sandbox_permissions":{"type":"string","description":"The wider sandbox mode this command needs. Only valid as a one-shot retry of a command the sandbox just denied; requires justification and user approval.","enum":["workspace-write","danger-full-access"]},"justification":{"type":"string","description":"Required with sandbox_permissions: one sentence for the user explaining why this exact command needs the wider access."}},"required":["command","description"]}},{"name":"bash_kill","description":"Ask the executor to kill a running background bash task by task id.","parameters":{"type":"object","properties":{"task_id":{"type":"string","description":"Task id returned by the bash tool."}},"required":["task_id"]}},{"name":"bash_output","description":"Read new output from a background bash task started with `bash` + `run_in_background`. Returns only output produced since the previous bash_output call, plus the task status. Tasks keep running while you do other work; poll again later for more output.","parameters":{"type":"object","properties":{"task_id":{"type":"string","description":"Task id returned by the bash tool."}},"required":["task_id"]}},{"name":"skill","description":"Load the full instructions for an available skill. Call this with the exact skill name from the session skill catalog before acting on a task that names or clearly matches that skill.","parameters":{"type":"object","properties":{"name":{"type":"string","description":"The exact skill name from the available skills list."}},"required":["name"]}}]},"reason":"initial"}}
+{"type":"request/header","seq":3,"time":1783613224997,"data":{"header":{"config":{"provider":"deepseek","model":"deepseek-v4-flash"},"system":"{{system}}","tools":[{"name":"bash","description":"Execute a bash command (`bash -c`) and return its stdout/stderr. Each call runs in a fresh shell: no state (cwd, variables, functions) persists between calls — pass `workdir` instead of using `cd`. Non-zero exits are reported as `[exit code: N]`. Commands may run under a file sandbox; a blocked file operation is reported as `[sandbox: file access denied under <mode> mode]` — a policy denial, not a bug in the command; do not retry another way (a background task reports the same marker via bash_output once it has finished). Long output is truncated to its tail; the full output is saved to a file whose path is reported when available. Set `run_in_background: true` for long-running commands: the call returns a task id immediately; poll it with `bash_output` and stop it with `bash_kill`. Attempting a command the sandbox may deny is safe and expected: run it and read the marker rather than assuming the denial. When a command IS denied and a wider mode would let it succeed, escalate immediately in the SAME turn — the ONE sanctioned exception to a denial: retry the exact same command once with `sandbox_permissions` (the narrowest wider mode that suffices) plus a one-sentence `justification`. Do not detour through chat to ask permission first — the approval prompt raised by that retry IS how the user consents. If the session states approval prompts are disabled, there is no exception: a denial is final — do not set `sandbox_permissions`. Never escalate speculatively: ground the request in a real denial — normally the one THIS command just hit; escalating up front is fine only when this session already denied the same access. A rejected escalation is final for THAT command — stop and explain, never work around it — but it does not forbid attempting or escalating other commands later.","parameters":{"type":"object","properties":{"command":{"type":"string","description":"The bash command to execute."},"description":{"type":"string","description":"Clear, concise description of what this command does in active voice, 5-10 words (shown in the UI). Examples: \"ls\" → \"List files in current directory\"; \"git status\" → \"Show working tree status\"; \"npm install\" → \"Install package dependencies\"."},"timeoutMs":{"type":"number","description":"Timeout in milliseconds. The executor applies its configured default and cap, and kills the command on expiry."},"workdir":{"type":"string","description":"Working directory for this command. Defaults to the session workspace; a relative path is resolved against it."},"run_in_background":{"type":"boolean","description":"Run in the background and return a task id immediately. No timeout applies."},"sandbox_permissions":{"type":"string","description":"The wider sandbox mode this command needs. Only valid as a one-shot retry of a command the sandbox just denied; requires justification and user approval.","enum":["workspace-write","danger-full-access"]},"justification":{"type":"string","description":"Required with sandbox_permissions: one sentence for the user explaining why this exact command needs the wider access."}},"required":["command","description"]}},{"name":"bash_kill","description":"Ask the executor to kill a running background bash task by task id.","parameters":{"type":"object","properties":{"task_id":{"type":"string","description":"Task id returned by the bash tool."}},"required":["task_id"]}},{"name":"bash_output","description":"Read new output from a background bash task started with `bash` + `run_in_background`. Returns only output produced since the previous bash_output call, plus the task status. Tasks keep running while you do other work; poll again later for more output.","parameters":{"type":"object","properties":{"task_id":{"type":"string","description":"Task id returned by the bash tool."}},"required":["task_id"]}},{"name":"skill","description":"Load the full instructions for an available skill. Call this with the exact skill name from the session skill catalog before acting on a task that names or clearly matches that skill.","parameters":{"type":"object","properties":{"name":{"type":"string","description":"The exact skill name from the available skills list."}},"required":["name"]}}]},"reason":"initial"}}
 {"type":"assistant/chunk","seq":4,"time":1783613225437,"data":{"turn":1,"step":1,"chunk":{"type":"block-start","index":0,"blockType":"reasoning"}}}
 {"type":"assistant/chunk","seq":5,"time":1783613225438,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":"The"}}}
 {"type":"assistant/chunk","seq":6,"time":1783613225658,"data":{"turn":1,"step":1,"chunk":{"type":"reasoning-delta","index":0,"text":" user"}}}
@@ -49,7 +49,7 @@
 {"type":"assistant/chunk","seq":47,"time":1783613226061,"data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_I9sT0gKlfz9YP4dlf2pA3899","name":"bash","arguments":"{\"command\": \"cat notes.txt\", \"description\": \"Show contents of notes.txt\"}"}}}}
 {"type":"assistant/chunk","seq":48,"time":1783613226061,"data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":1202,"outputTokens":81,"cacheReadTokens":0,"reasoningTokens":16}}}}
 {"type":"assistant/chunk","seq":49,"time":1783613226061,"data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":50,"time":1783613226064,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `cat notes.txt` using the bash tool."},{"type":"tool-call","id":"call_00_I9sT0gKlfz9YP4dlf2pA3899","name":"bash","arguments":"{\"command\": \"cat notes.txt\", \"description\": \"Show contents of notes.txt\"}"}],"usage":{"inputTokens":1202,"outputTokens":81,"cacheReadTokens":0,"reasoningTokens":16}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49],"surfaceOp":"append"}
+{"type":"assistant/message","seq":50,"time":1783613226064,"data":{"turn":1,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run `cat notes.txt` using the bash tool."},{"type":"tool-call","id":"call_00_I9sT0gKlfz9YP4dlf2pA3899","name":"bash","arguments":"{\"command\": \"cat notes.txt\", \"description\": \"Show contents of notes.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":1202,"outputTokens":81,"cacheReadTokens":0,"reasoningTokens":16}},"sourceEventSeqs":[4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49],"surfaceOp":"append"}
 {"type":"tool/call","seq":51,"time":1783613226064,"data":{"turn":1,"step":1,"callId":"call_00_I9sT0gKlfz9YP4dlf2pA3899","name":"bash","arguments":"{\"command\": \"cat notes.txt\", \"description\": \"Show contents of notes.txt\"}"}}
 {"type":"tool/result","seq":52,"time":1783613226148,"data":{"turn":1,"step":1,"callId":"call_00_I9sT0gKlfz9YP4dlf2pA3899","content":[{"type":"text","text":"hello from the sandboxed workspace\n"}],"isError":false},"sourceEventSeqs":[51],"surfaceOp":"append"}
 {"type":"step/end","seq":53,"time":1783613226148,"data":{"turn":1,"step":1}}
@@ -80,7 +80,7 @@
 {"type":"assistant/chunk","seq":78,"time":1783613227141,"data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":79,"time":1783613227141,"data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":23,"outputTokens":21,"cacheReadTokens":1280,"reasoningTokens":18}}}}
 {"type":"assistant/chunk","seq":80,"time":1783613227141,"data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":81,"time":1783613227142,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command ran successfully. The user asked me to reply with the single word DONE."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":23,"outputTokens":21,"cacheReadTokens":1280,"reasoningTokens":18}},"sourceEventSeqs":[55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80],"surfaceOp":"append"}
+{"type":"assistant/message","seq":81,"time":1783613227142,"data":{"turn":1,"step":2,"content":[{"type":"reasoning","text":"The command ran successfully. The user asked me to reply with the single word DONE."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":23,"outputTokens":21,"cacheReadTokens":1280,"reasoningTokens":18}},"sourceEventSeqs":[55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80],"surfaceOp":"append"}
 {"type":"step/end","seq":82,"time":1783613227142,"data":{"turn":1,"step":2}}
 {"type":"turn/end","seq":83,"time":1783613227142,"data":{"turn":1,"reason":{"kind":"completed"}}}
 {"type":"turn/start","seq":84,"time":1783613227169,"data":{"turn":2,"trigger":{"kind":"message","source":{"kind":"user"}}}}
@@ -142,7 +142,7 @@
 {"type":"assistant/chunk","seq":140,"time":1783613228325,"data":{"turn":2,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"tool-call","id":"call_00_htXcbtvwTFK0NqfclLWL7784","name":"bash","arguments":"{\"description\": \"Write and read out.txt\", \"command\": \"printf 'switched\\\\n' > out.txt && cat out.txt\"}"}}}}
 {"type":"assistant/chunk","seq":141,"time":1783613228325,"data":{"turn":2,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":70,"outputTokens":90,"cacheReadTokens":1280,"reasoningTokens":15}}}}
 {"type":"assistant/chunk","seq":142,"time":1783613228325,"data":{"turn":2,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","seq":143,"time":1783613228325,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a specific command. Let me execute it."},{"type":"tool-call","id":"call_00_htXcbtvwTFK0NqfclLWL7784","name":"bash","arguments":"{\"description\": \"Write and read out.txt\", \"command\": \"printf 'switched\\\\n' > out.txt && cat out.txt\"}"}],"usage":{"inputTokens":70,"outputTokens":90,"cacheReadTokens":1280,"reasoningTokens":15}},"sourceEventSeqs":[88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142],"surfaceOp":"append"}
+{"type":"assistant/message","seq":143,"time":1783613228325,"data":{"turn":2,"step":1,"content":[{"type":"reasoning","text":"The user wants me to run a specific command. Let me execute it."},{"type":"tool-call","id":"call_00_htXcbtvwTFK0NqfclLWL7784","name":"bash","arguments":"{\"description\": \"Write and read out.txt\", \"command\": \"printf 'switched\\\\n' > out.txt && cat out.txt\"}"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":70,"outputTokens":90,"cacheReadTokens":1280,"reasoningTokens":15}},"sourceEventSeqs":[88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142],"surfaceOp":"append"}
 {"type":"tool/call","seq":144,"time":1783613228325,"data":{"turn":2,"step":1,"callId":"call_00_htXcbtvwTFK0NqfclLWL7784","name":"bash","arguments":"{\"description\": \"Write and read out.txt\", \"command\": \"printf 'switched\\\\n' > out.txt && cat out.txt\"}"}}
 {"type":"tool/result","seq":145,"time":1783613228412,"data":{"turn":2,"step":1,"callId":"call_00_htXcbtvwTFK0NqfclLWL7784","content":[{"type":"text","text":"switched\n"}],"isError":false},"sourceEventSeqs":[144],"surfaceOp":"append"}
 {"type":"step/end","seq":146,"time":1783613228412,"data":{"turn":2,"step":1}}
@@ -166,7 +166,7 @@
 {"type":"assistant/chunk","seq":164,"time":1783613229048,"data":{"turn":2,"step":2,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","seq":165,"time":1783613229048,"data":{"turn":2,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":47,"outputTokens":14,"cacheReadTokens":1408,"reasoningTokens":11}}}}
 {"type":"assistant/chunk","seq":166,"time":1783613229048,"data":{"turn":2,"step":2,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":167,"time":1783613229049,"data":{"turn":2,"step":2,"content":[{"type":"reasoning","text":"Command executed successfully. The output is \"switched\"."},{"type":"text","text":"DONE"}],"usage":{"inputTokens":47,"outputTokens":14,"cacheReadTokens":1408,"reasoningTokens":11}},"sourceEventSeqs":[148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166],"surfaceOp":"append"}
+{"type":"assistant/message","seq":167,"time":1783613229049,"data":{"turn":2,"step":2,"content":[{"type":"reasoning","text":"Command executed successfully. The output is \"switched\"."},{"type":"text","text":"DONE"}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":47,"outputTokens":14,"cacheReadTokens":1408,"reasoningTokens":11}},"sourceEventSeqs":[148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166],"surfaceOp":"append"}
 {"type":"step/end","seq":168,"time":1783613229049,"data":{"turn":2,"step":2}}
 {"type":"turn/end","seq":169,"time":1783613229049,"data":{"turn":2,"reason":{"kind":"completed"}}}
 {"type":"turn/start","seq":170,"time":1783613229056,"data":{"turn":3,"trigger":{"kind":"message","source":{"kind":"user"}}}}
@@ -240,6 +240,6 @@
 {"type":"assistant/chunk","seq":238,"time":1783613230689,"data":{"turn":3,"step":1,"chunk":{"type":"block-end","index":1,"block":{"type":"text","text":"Approvals are never asked; any action requiring approval is automatically rejected."}}}}
 {"type":"assistant/chunk","seq":239,"time":1783613230689,"data":{"turn":3,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":1530,"outputTokens":60,"cacheReadTokens":0,"reasoningTokens":45}}}}
 {"type":"assistant/chunk","seq":240,"time":1783613230689,"data":{"turn":3,"step":1,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","seq":241,"time":1783613230690,"data":{"turn":3,"step":1,"content":[{"type":"reasoning","text":"The user wants me to state my current approval policy without using any tools. From the context, the approval policy is \"never\" — meaning actions that require approval are rejected automatically, and I should not request sandbox escalation."},{"type":"text","text":"Approvals are never asked; any action requiring approval is automatically rejected."}],"usage":{"inputTokens":1530,"outputTokens":60,"cacheReadTokens":0,"reasoningTokens":45}},"sourceEventSeqs":[176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240],"surfaceOp":"append"}
+{"type":"assistant/message","seq":241,"time":1783613230690,"data":{"turn":3,"step":1,"content":[{"type":"reasoning","text":"The user wants me to state my current approval policy without using any tools. From the context, the approval policy is \"never\" — meaning actions that require approval are rejected automatically, and I should not request sandbox escalation."},{"type":"text","text":"Approvals are never asked; any action requiring approval is automatically rejected."}],"provenance":{"provider":"deepseek","model":"deepseek-v4-flash"},"usage":{"inputTokens":1530,"outputTokens":60,"cacheReadTokens":0,"reasoningTokens":45}},"sourceEventSeqs":[176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240],"surfaceOp":"append"}
 {"type":"step/end","seq":242,"time":1783613230690,"data":{"turn":3,"step":1}}
 {"type":"turn/end","seq":243,"time":1783613230690,"data":{"turn":3,"reason":{"kind":"completed"}}}
--- a/packages/bash/tool-bash/tests/integration.spec.ts
+++ b/packages/bash/tool-bash/tests/integration.spec.ts
@@ -74,7 +74,7 @@ describe('bash tool through the agent loop', () => {
      textResponse('The command printed integration-ok.'),
    ])
    const ctx = await harness(adapter)
-    const agent = ctx.agentLoop.create(AgentId('it-fg'), { model: 'mock' })
+    const agent = ctx.agentLoop.create(AgentId('it-fg'), { provider: 'mock', model: 'mock' })

    agent.send([{ type: 'text', text: 'run echo integration-ok' }])
    await waitForIdle(ctx, agent)
@@ -106,7 +106,7 @@ describe('bash tool through the agent loop', () => {
      textResponse('It failed with code 9.'),
    ])
    const ctx = await harness(adapter)
-    const agent = ctx.agentLoop.create(AgentId('it-exit'), { model: 'mock' })
+    const agent = ctx.agentLoop.create(AgentId('it-exit'), { provider: 'mock', model: 'mock' })

    agent.send([{ type: 'text', text: 'run exit 9' }])
    await waitForIdle(ctx, agent)
@@ -128,7 +128,7 @@ describe('bash tool through the agent loop', () => {
    let taskId = ''

    const ctx = await harness(adapter)
-    const agent = ctx.agentLoop.create(AgentId('it-bg'), { model: 'mock' })
+    const agent = ctx.agentLoop.create(AgentId('it-bg'), { provider: 'mock', model: 'mock' })

    // Capture the generated id so the deterministic fixture is checked against
    // the real executor instead of silently assuming it.
--- a/packages/compact/compact-basic/README.md
+++ b/packages/compact/compact-basic/README.md
@@ -11,13 +11,13 @@ The abstract contract states only WHAT compaction does; this backend owns every
 - **Token estimation** — `estimateContentTokens()`: chars divided by the `charsPerToken` config (default 4) with per-block structural overhead (`text`/`reasoning` = `ceil(len/charsPerToken) + 4`, `tool-call` from name + arguments, `tool-result` recursive, unknown blocks via JSON length). The pressure gate estimates the NEXT request via `estimatePressure()`: the session prefix (the `agent/session-prefix` product — composed by the loop BEFORE the pre-step seam and handed through it, so the gate counts the prefix this instance will actually send in front of the history, never a stale logged one) + the derived history + the system prompt.
 - **Retention policy** — `compactIfNeeded()` walks the surface nodes tail→head summing per-node token estimates, and retains the smallest tail-run of WHOLE units (a closed step, or a single no-step node such as a pre-step `user/message` or inter-step `steering/message`) whose total reaches `retainTokens`; everything older is compacted. Retention is **turn-agnostic** — turn boundaries play no role, so a single runaway turn that alone exceeds the window compacts its OWN early closed steps rather than being retained verbatim (the failure mode that motivated dropping turn-protection: a tool-heavy turn must stay compactable or the harness dies exactly when compaction is needed). The only structural guard is **tool-pairing balance**: the compacted region's edges are balanced cuts on the surface (no unanswered tool-call crosses either edge), so it never splits a step's `assistant/message` tool-calls from their `tool/result`s. When the only compactable content left is an un-splittable open tail step, it declines (returns `null`) and retries once an older step closes. **Single-unit overflow is out of scope, by design**: if one retained unit (a single closed step, or a large pasted `user/message`) ALONE exceeds the budget, compaction cannot help and the call may go out over-budget — bounding an individual unit's size is a separate concern. `compactRegion()` enforces tool-pairing balance strictly, throwing on a boundary that would split a step. `dsh-session` exports `isToolPairingBalanced` for the check.
 - **Dynamic convergence** — no static summary-length config pretends to bound what the model will write. If framing/estimator/system overhead leaves the compacted surface above threshold, `compactIfNeeded()` re-compacts the head checkpoint up to `compactionRetries` extra times; if it still cannot get below threshold, it throws. A summary whose estimated stored size is not smaller than the shadowed content fails closed before it mutates the surface.
- **Summarization** — `summarize()`: a `GenerateOptions` request assembled via `BlockAssembler` with a fixed system prompt that asks for a structured checkpoint (Primary Request and Intent · Key Technical Concepts · Files and Code · Errors and Fixes · Pending Tasks · Current Work · Next Step · Critical Context), every section mandatory, exact paths/commands/identifiers preserved. The request is a direct one-shot `ctx.llm.stream()` call — NOT a loop step, so it does not run `agent/request` (that seam shapes the loop's conversation requests); the model comes from `summarizationModel` falling back to the agent's own, and per-call routing happens at `llm/stream` like any other direct call. `maxTokens` is the provider-side generation cap; only text blocks from the model's reply are kept before the checkpoint is stored (reasoning is dropped so private chain-of-thought never leaks into the durable summary, and a stray `tool-call` is dropped so the synthesized `user/message` summary cannot land an orphaned call with no matching `tool-result`). The compacted region is flattened to a plain-text transcript first: text and reasoning contribute their text, and every non-text block (tool-call, tool-result, plugin-added types) contributes a type-tagged placeholder (`[tool-call: name(args)]`, `[tool-result: …]`, …) so the summarizer is told what existed rather than silently dropping it.
+- **Summarization** — `summarize()`: a `GenerateOptions` request assembled via `BlockAssembler` with a fixed system prompt that asks for a structured checkpoint (Primary Request and Intent · Key Technical Concepts · Files and Code · Errors and Fixes · Pending Tasks · Current Work · Next Step · Critical Context), every section mandatory, exact paths/commands/identifiers preserved. The request is a direct one-shot `ctx.llm.stream()` call — NOT a loop step, so it does not run `agent/request` (that seam shapes the loop's conversation requests); the target comes from the explicit `summarizationProvider`+`summarizationModel` pair, otherwise the latest logged request pair, otherwise the agent pair. Per-call routing happens at `llm/stream` like any other direct call. `maxTokens` is the provider-side generation cap; only text blocks from the model's reply are kept before the checkpoint is stored (reasoning is dropped so private chain-of-thought never leaks into the durable summary, and a stray `tool-call` is dropped so the synthesized `user/message` summary cannot land an orphaned call with no matching `tool-result`). The compacted region is flattened to a plain-text transcript first: text and reasoning contribute their text, and every non-text block (tool-call, tool-result, plugin-added types) contributes a type-tagged placeholder (`[tool-call: name(args)]`, `[tool-result: …]`, …) so the summarizer is told what existed rather than silently dropping it.
 - **Checkpoint framing** — the raw summary is not landed directly. `compactRegion()` wraps it in a checkpoint preamble (so a resuming model reads it as a checkpoint, not a fresh user request, and builds on the captured context rather than restating it) plus `<compacted-summary>…</compacted-summary>` tags. Because region compaction can be invoked manually, a surface may hold several checkpoints, so the framing does not claim everything after it is recent or verbatim. The tags make a prior checkpoint detectable in the transcript on the next compaction cycle: the summarization prompt then instructs the model to merge it in place (preserve still-true facts, drop stale ones) rather than re-summarize it verbatim — a cheap incremental merge that needs no extra log/event machinery. The unframed summary stays on the `compact/summary` provenance event.
 - **Surface mutation** — `compactRegion()` appends the `compact/start` → `compact/summary` → `compact/end` log records and the single `user/message` replace node carrying the framed summary (see the interface README).
 - **Auto-compaction** — an `agent/pre-step` listener delegates to `compactIfNeeded()` before every step (not just a turn's first — a tool-heavy turn grows the surface mid-turn, so a runaway turn still compacts, and per-step firing is the only moment to rescue it before overflow). `agent/pre-step` is a serial (awaited, in-order) surface-mutation checkpoint that fires after `turn/start` and BEFORE the step opens (`step/start`) and its request history is derived, so compaction mutates the surface — with its log-only `compact/*` records landing cleanly outside any step — and the loop derives once from the result: no double-derive, and the listener cannot see (or need to rewrite) an already-assembled `messages` array. The listener owns no threshold logic of its own (the single token-pressure check lives in `compactIfNeeded()`); because Cordis `serial` bails early on non-void return values, the listener returns `void` and does not use the dispatcher's bail channel as a veto surface.
 - **Failure handling** — the `compact/start … compact/end` bracket is a log-recorded lock: it makes a crash mid-summarization a detectable orphan (a `compact/start` with no `compact/end`), records provenance, and prevents a concurrent compaction. Two failure paths: a **crash** (the loop dies mid-summarization) leaves a dangling `compact/start` that is inert — `compact/*` events are log-only, the surface replacement never landed, so the full history derives fine and generic turn-repair closes the turn; a **recoverable** failure (summarization throws but the loop survives) appends `compact/end` with its `error` field set, leaving the surface untouched so the call proceeds with full history. Core session repair stays compaction-agnostic by design — it never learns about `compact/*`.

-`estimateContentTokens()` and `summarize()` are overridable hooks: a tokenizer-based or template-based backend can subclass `BasicCompactService` and override just those, reusing the retention walk and surface plumbing. `summarize()` returns the summary blocks together with the call envelope it actually used (`{ summary, model, maxTokens? }`) — the caller logs that envelope on the `compact/summary` provenance event, so an overriding backend reports its own envelope honestly.
+`estimateContentTokens()` and `summarize()` are overridable hooks: a tokenizer-based or template-based backend can subclass `BasicCompactService` and override just those, reusing the retention walk and surface plumbing. `summarize()` returns the summary blocks together with the call envelope it actually used (`{ summary, provider, model, maxTokens? }`) — the caller logs that envelope on the `compact/summary` provenance event, so an overriding backend reports its own envelope honestly.

 ## Config (`BasicCompactConfig`)

@@ -28,7 +28,8 @@ Every knob is **required** except `auto` — there is no concrete data yet to ju
 | `contextWindow` | yes | Context window size in tokens. |
 | `thresholdRatio` | yes | Compact when estimated usage exceeds this fraction of the window. |
 | `retainTokens` | yes | Tokens of recent context to keep intact. |
-| `summarizationModel` | yes | Model for summarization (`''` → use the agent's model). |
+| `summarizationProvider` | yes | Provider for summarization (`''` together with an empty model → use the latest logged request pair, then the agent pair). |
+| `summarizationModel` | yes | Model for summarization (`''` together with an empty provider → use the latest logged request pair, then the agent pair). |
 | `maxTokens` | yes | Provider generation cap for the summarization call; may include reasoning tokens. |
 | `compactionRetries` | yes | Extra compaction attempts after the first if the compacted surface remains over threshold. |
 | `auto` | no (default `true`) | Register the `agent/pre-step` auto-compaction listener. Set `false` for manual-only. |
@@ -48,6 +49,7 @@ export function apply(ctx: Context): void {
    contextWindow: 128000,
    thresholdRatio: 0.8,
    retainTokens: 20480,
+    summarizationProvider: '',
    summarizationModel: '',
    maxTokens: 8192,
    compactionRetries: 1,
--- a/packages/compact/compact-basic/src/index.ts
+++ b/packages/compact/compact-basic/src/index.ts
@@ -294,8 +294,8 @@ export class BasicCompactService extends CompactService {
   * loop step: it does not run the `agent/request` waterfall (that seam shapes
   * the loop's conversation requests); per-call
   * interception happens at `llm/stream` like any other direct call. The model
-   * comes from `BasicCompactConfig.summarizationModel`, falling back to the
-   * agent's own model.
+   * target comes from the explicit summarization provider/model pair, falling
+   * back to the last logged request target and then the agent's creation options.
   * Override in a subclass for a template or remote summarizer.
   *
   * Honors the adapter failure contract: an adapter may report a model failure
@@ -307,23 +307,27 @@ export class BasicCompactService extends CompactService {
   * down the in-flight summarization rather than orphaning the model call.
   *
   * Returns the summary blocks TOGETHER with the call envelope it actually
-   * used (`model`, `maxTokens`) — the caller logs the envelope on the
+   * used (`provider`, `model`, `maxTokens`) — the caller logs the envelope on the
   * `compact/summary` provenance event, so an overriding subclass (template
   * or remote summarizer) reports its own envelope honestly.
   *
   * @param text - plain-text rendering of the conversation region to condense.
-   * @param agent - supplies the fallback model and the session id stamped on
-   *   the call; throws when neither it nor the config names a model.
+   * @param agent - supplies the request-header/creation fallback target and the
+   *   session id stamped on the call; throws when no complete target exists.
   * @param signal - optional abort signal, forwarded into the model call.
   * @returns the text-only summary blocks plus the call envelope used
-   *   (`model`, and `maxTokens` when the summarizer has a cap).
+   *   (`provider`, `model`, and `maxTokens` when the summarizer has a cap).
   */
  async summarize(
    text: string, agent: Agent, signal?: AbortSignal,
-  ): Promise<{ summary: ContentBlock[]; model: string; maxTokens?: number }> {
+  ): Promise<{ summary: ContentBlock[]; provider: string; model: string; maxTokens?: number }> {
    const assembler = new BlockAssembler()
+    const logged = agent.session.requestHeader()?.config
+    const provider = this.config.summarizationProvider || logged?.provider || agent.options.provider || ''
+    const model = this.config.summarizationModel || logged?.model || agent.options.model || ''
    const options: GenerateOptions = {
-      model: this.config.summarizationModel || agent.options.model || '',
+      provider,
+      model,
      messages: [{
        role: 'user',
        content: [{ type: 'text', text: `Summarize this conversation history:\n\n${text}\n\nSummary:` }],
@@ -335,8 +339,8 @@ export class BasicCompactService extends CompactService {
    // exactOptionalPropertyTypes: only set `signal` when present — assigning
    // `undefined` to an optional `signal?: AbortSignal` is a type error.
    if (signal) options.signal = signal
-    if (!options.model) {
-      throw new Error('no model available for summarization: set BasicCompactConfig.summarizationModel or AgentOptions.model')
+    if (!options.provider || !options.model) {
+      throw new Error('no provider/model available for summarization: set both summarization fields or provide a logged/agent target')
    }
    for await (const chunk of this.ctx.llm.stream(options)) {
      assembler.push(chunk)
@@ -353,7 +357,7 @@ export class BasicCompactService extends CompactService {
    // config.maxTokens is required and validated positive, so this backend's
    // envelope always carries the cap; the return type's optionality exists
    // for overriding subclasses whose summarizer has none.
-    return { summary, model: options.model, maxTokens: this.config.maxTokens }
+    return { summary, provider: options.provider, model: options.model, maxTokens: this.config.maxTokens }
  }

  // ---- Core API (implements the abstract contract) ----
@@ -511,7 +515,7 @@ export class BasicCompactService extends CompactService {
    try {
      // --- Extract text and summarize ---
      const text = renderTranscript(session.events, shadowedSeqs)
-      const { summary, model, maxTokens } = await this.summarize(text, agent, signal)
+      const { summary, provider, model, maxTokens } = await this.summarize(text, agent, signal)

      // Estimate token count of the shadowed content for provenance.
      let shadowedTokenCount = 0
@@ -533,6 +537,7 @@ export class BasicCompactService extends CompactService {
        shadowedRange: { start, end },
        shadowedSeqs,
        shadowedTokenCount,
+        provider,
        model,
        ...maxTokens !== undefined ? { maxTokens } : {},
      })
--- a/packages/compact/compact-basic/src/types.ts
+++ b/packages/compact/compact-basic/src/types.ts
@@ -24,7 +24,9 @@ export interface BasicCompactConfig {
  thresholdRatio: number
  /** Number of tokens of recent context to retain during compaction. */
  retainTokens: number
-  /** Model to use for summarization (`''` — uses the agent's model). */
+  /** Provider to use for summarization (`''` with an empty model inherits the conversation target). */
+  summarizationProvider: string
+  /** Model to use for summarization (`''` with an empty provider inherits the conversation target). */
  summarizationModel: string
  /** Provider generation cap for the summarization call. */
  maxTokens: number
@@ -70,6 +72,12 @@ export function resolveConfig(config: BasicCompactConfig): ResolvedConfig {
  if (typeof resolved.summarizationModel !== 'string') {
    throw new Error('BasicCompactConfig: summarizationModel must be a string.')
  }
+  if (typeof resolved.summarizationProvider !== 'string') {
+    throw new Error('BasicCompactConfig: summarizationProvider must be a string.')
+  }
+  if ((resolved.summarizationProvider.length === 0) !== (resolved.summarizationModel.length === 0)) {
+    throw new Error('BasicCompactConfig: summarizationProvider and summarizationModel must both be empty or both be set.')
+  }
  if (typeof resolved.auto !== 'boolean') {
    throw new Error('BasicCompactConfig: auto must be a boolean.')
  }
--- a/packages/compact/compact-basic/tests/compact-basic.spec.ts
+++ b/packages/compact/compact-basic/tests/compact-basic.spec.ts
@@ -21,6 +21,7 @@ const TEST_CONFIG: BasicCompactConfig = {
  contextWindow: 128000,
  thresholdRatio: 0.8,
  retainTokens: 20480,
+  summarizationProvider: '',
  summarizationModel: '',
  maxTokens: 8192,
  compactionRetries: 1,
@@ -58,13 +59,17 @@ class TestCompactService extends BasicCompactService {
    return blocks.length * 10
  }

-  override async summarize(text: string, agent: Agent): Promise<{ summary: ContentBlock[]; model: string; maxTokens?: number }> {
+  override async summarize(
+    text: string,
+    agent: Agent,
+  ): Promise<{ summary: ContentBlock[]; provider: string; model: string; maxTokens?: number }> {
+    const provider = this.config.summarizationProvider || agent.options.provider || ''
    const model = this.config.summarizationModel || agent.options.model || ''
    this.summarizeCalls.push({ text, model })
    if (this.summarizeError) throw this.summarizeError
    const summary = this.mockSummaryQueue.shift() ?? this.mockSummary
    this.summaryOutputs.add(summary)
-    return { summary, model }
+    return { summary, provider, model }
  }
 }

@@ -102,7 +107,7 @@ function multiTurnSession(turns: number, messagesPerTurn: number = 2, opts: { le
        content: [{ type: 'text', text: `turn ${t} user message ${m + 1}.${LONG_FIXTURE_TEXT}` }],
        source: { kind: 'user' },
      }, { surfaceOp: 'append' })
-      s.append('assistant/message', {
+      s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
        turn: t, step: 1,
        content: [{ type: 'text', text: `turn ${t} assistant response ${m + 1}.${LONG_FIXTURE_TEXT}` }],
      }, { surfaceOp: 'append' })
@@ -127,7 +132,7 @@ function sessionWithTools(): Session {
    content: [{ type: 'text', text: 'read file x' }],
    source: { kind: 'user' },
  }, { surfaceOp: 'append' })
-  s.append('assistant/message', {
+  s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
    turn: 1, step: 1,
    content: [
      { type: 'text', text: 'Let me read that file.' },
@@ -140,7 +145,7 @@ function sessionWithTools(): Session {
    content: [{ type: 'text', text: 'hello world' }],
    isError: false,
  }, { surfaceOp: 'append' })
-  s.append('assistant/message', {
+  s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
    turn: 1, step: 1,
    content: [{ type: 'text', text: 'The file contains: hello world' }],
  }, { surfaceOp: 'append' })
@@ -169,7 +174,7 @@ function toolTurnSession(turns: number): Session {
      source: { kind: 'user' },
    }, { surfaceOp: 'append' })
    s.append('step/start', { turn: t, step: 1 })
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: t, step: 1,
      content: [
        { type: 'text', text: `turn ${t} calling tool` },
@@ -240,7 +245,7 @@ describe('BasicCompactService step-alignment (never split a tool-call/result pai
    const s = new Session(SessionId('one-step'))
    s.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
    s.append('step/start', { turn: 1, step: 1 })
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 1,
      content: [{ type: 'text', text: 'calling' }, { type: 'tool-call', id: CallId('c1'), name: 'bash', arguments: '{}' }],
    }, { surfaceOp: 'append' })
@@ -286,7 +291,7 @@ describe('BasicCompactService step-alignment (never split a tool-call/result pai
    s.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
    s.append('user/message', { content: [{ type: 'text', text: 'go' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
    s.append('step/start', { turn: 1, step: 1 })
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 1,
      content: [{ type: 'tool-call', id: CallId('c1'), name: 'bash', arguments: '{}' }],
    }, { surfaceOp: 'append' })
@@ -348,7 +353,7 @@ describe('BasicCompactService.estimateEventTokens', () => {
    const userEvent: SessionEvent = { type: 'user/message', seq: 0, time: 1, data: { content: [{ type: 'text', text: 'hello' }], source: { kind: 'user' } } }
    expect(svc.estimateEventTokens(userEvent)).toBe(10)

-    const asstEvent: SessionEvent = { type: 'assistant/message', seq: 1, time: 2, data: { turn: 1, step: 1, content: [{ type: 'text', text: 'a' }, { type: 'text', text: 'b' }] } }
+    const asstEvent: SessionEvent = { type: 'assistant/message', seq: 1, time: 2, data: { turn: 1, step: 1, content: [{ type: 'text', text: 'a' }, { type: 'text', text: 'b' }], provenance: { provider: 'mock', model: 'mock' } } }
    expect(svc.estimateEventTokens(asstEvent)).toBe(20)

    const toolEvent: SessionEvent = { type: 'tool/result', seq: 2, time: 3, data: { turn: 1, step: 1, callId: CallId('c1'), content: [{ type: 'text', text: 'output' }], isError: false } }
@@ -633,7 +638,7 @@ describe('BasicCompactService.compactIfNeeded', () => {
    s.append('user/message', { content: [{ type: 'text', text: 'do a big multi-step task' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
    for (let step = 1; step <= 5; step++) {
      s.append('step/start', { turn: 1, step })
-      s.append('assistant/message', {
+      s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
        turn: 1, step,
        content: [{ type: 'text', text: `step ${step}` }, { type: 'tool-call', id: CallId(`c${step}`), name: 'bash', arguments: '{}' }],
      }, { surfaceOp: 'append' })
@@ -686,7 +691,7 @@ describe('BasicCompactService.compactIfNeeded', () => {
    // the fresh nodes are retained.
    s.append('step/start', { turn: 5, step: 1 })
    s.append('user/message', { content: [{ type: 'text', text: 'turn 5 work' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    s.append('assistant/message', { turn: 5, step: 1, content: [{ type: 'text', text: 'reply 5' }] }, { surfaceOp: 'append' })
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' }, turn: 5, step: 1, content: [{ type: 'text', text: 'reply 5' }] }, { surfaceOp: 'append' })
    s.append('step/end', { turn: 5, step: 1 })

    const second = await compactIfNeeded(svc, s, '', 'm', SIGNAL)
@@ -785,7 +790,7 @@ describe('BasicCompactService blocking (compaction in progress)', () => {
    s.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
    s.append('step/start', { turn: 1, step: 1 })
    s.append('user/message', { content: [{ type: 'text', text: 'turn 1' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    s.append('assistant/message', { turn: 1, step: 1, content: [{ type: 'text', text: 'reply 1' }] }, { surfaceOp: 'append' })
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' }, turn: 1, step: 1, content: [{ type: 'text', text: 'reply 1' }] }, { surfaceOp: 'append' })
    s.append('compact/start', { turn: 1 }) // ← orphaned: no matching compact/end
    s.append('step/end', { turn: 1, step: 1 })
    s.append('turn/end', { turn: 1, reason: { kind: 'completed' } }) // repair closed the turn
@@ -991,7 +996,7 @@ async function ctxWithFinish(reason: (StreamChunk & { type: 'finish' })['reason'

 /** A minimal Agent stub carrying just session + options (enough for the listeners). */
 function stubAgent(session: Session, model?: string): Agent {
-  return { session, options: { model } } as unknown as Agent
+  return { session, options: { provider: model, model } } as unknown as Agent
 }

 function compactIfNeeded(
@@ -1076,7 +1081,7 @@ describe('BasicCompactService.summarize (real ctx.llm.stream)', () => {
  it('throws when no model is provided', async () => {
    const { ctx } = await ctxWithModel('x')
    const svc = new BasicCompactService(ctx, cfg({ auto: false }))
-    await expect(summarize(svc, 'text', '')).rejects.toThrow(/no model available/)
+    await expect(summarize(svc, 'text', '')).rejects.toThrow(/no provider\/model available/)
  })

  it('rethrows when the stream ends with a finish-error chunk', async () => {
@@ -1153,7 +1158,7 @@ describe('BasicCompactService.summarize (real ctx.llm.stream)', () => {
    session.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
    session.append('step/start', { turn: 1, step: 1 })
    session.append('user/message', { content: [{ type: 'text', text: 'tiny user' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    session.append('assistant/message', { turn: 1, step: 1, content: [{ type: 'text', text: 'tiny assistant' }] }, { surfaceOp: 'append' })
+    session.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' }, turn: 1, step: 1, content: [{ type: 'text', text: 'tiny assistant' }] }, { surfaceOp: 'append' })
    session.append('step/end', { turn: 1, step: 1 })
    session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
    session.append('turn/start', { turn: 2, trigger: { kind: 'message', source: { kind: 'user' } } })
@@ -1262,9 +1267,10 @@ describe('BasicCompactService auto-compaction (agent/pre-step listener)', () =>
    // The summarize call is a direct one-shot model call, not a loop step: it
    // does not run agent/request (that seam shapes the loop's conversation
    // requests). llm/stream is its interception surface, and a hand-built
-    // request is not frozen, so mutate-then-next model routing works — the
-    // adapter resolves AFTER the waterfall, so the rewrite picks the adapter.
+    // request is not frozen, so mutate-then-next provider/model routing works —
+    // the adapter resolves AFTER the waterfall, so the rewrite picks it.
    ctx.on('llm/stream', (options, next) => {
+      options.provider = 'routed-model'
      options.model = 'routed-model'
      return next()
    })
@@ -1307,7 +1313,7 @@ describe('BasicCompactService transcript rendering (delegated to dsh-compact)',
      content: [{ type: 'text', text: 'project context here' }],
      source: { kind: 'user' },
    }, { surfaceOp: 'append' })
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 1,
      content: [{ type: 'reasoning', text: 'thinking hard' }, { type: 'text', text: 'answer' }],
    }, { surfaceOp: 'append' })
@@ -1335,7 +1341,7 @@ describe('BasicCompactService transcript rendering (delegated to dsh-compact)',
    s.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
    s.append('step/start', { turn: 1, step: 1 })
    s.append('user/message', { content: [{ type: 'text', text: 'run it' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 1,
      content: [{ type: 'tool-call', id: CallId('c9'), name: 'bash', arguments: '{}' }],
    }, { surfaceOp: 'append' })
@@ -1364,7 +1370,7 @@ describe('BasicCompactService edge cases', () => {
    // assistant/message carrying a nested tool-result block, an unknown block,
    // and the tool-call that the following tool/result answers (so the surface
    // is tool-pairing balanced).
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 1,
      content: [
        { type: 'tool-result', toolCallId: CallId('n1'), content: [{ type: 'chart', data: 'x' } as unknown as ContentBlock] },
@@ -1427,7 +1433,7 @@ describe('BasicCompactService edge cases', () => {
    s.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
    s.append('step/start', { turn: 1, step: 1 })
    s.append('user/message', { content: [{ type: 'text', text: 'orphan' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    s.append('assistant/message', { turn: 1, step: 1, content: [{ type: 'text', text: 'reply' }] }, { surfaceOp: 'append' })
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' }, turn: 1, step: 1, content: [{ type: 'text', text: 'reply' }] }, { surfaceOp: 'append' })
    s.append('step/end', { turn: 1, step: 1 })
    s.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
    const nodes = s.surface.nodes
@@ -1522,7 +1528,7 @@ describe('BasicCompactService edge cases', () => {
    // nothing and are skipped.
    s.append('step/start', { turn: 1, step: 1 })
    s.append('user/message', { content: [{ type: 'text', text: '' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    s.append('assistant/message', { turn: 1, step: 1, content: [{ type: 'reasoning', text: '' }] }, { surfaceOp: 'append' })
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' }, turn: 1, step: 1, content: [{ type: 'reasoning', text: '' }] }, { surfaceOp: 'append' })
    s.append('context/message', { content: [], source: { kind: 'user' } }, { surfaceOp: 'append' })
    s.append('steering/message', { turn: 1, content: [{ type: 'text', text: '' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
    s.append('step/end', { turn: 1, step: 1 })
@@ -1531,7 +1537,7 @@ describe('BasicCompactService edge cases', () => {
    // surface stays tool-pairing balanced; its text extracts to the tool-call
    // placeholder (the one surviving line).
    s.append('step/start', { turn: 1, step: 2 })
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 2,
      content: [{ type: 'tool-call', id: CallId('z1'), name: 'bash', arguments: '{}' }],
    }, { surfaceOp: 'append' })
@@ -1562,7 +1568,7 @@ describe('BasicCompactService edge cases', () => {
    s.append('user/message', { content: [chart('y')], source: { kind: 'user' } }, { surfaceOp: 'append' })
    // assistant/message with a plugin-added block AND the tool-call its
    // tool/result answers (so the surface is tool-pairing balanced).
-    s.append('assistant/message', {
+    s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 1, step: 1,
      content: [
        chart('z'),
@@ -1713,7 +1719,7 @@ describe('BasicCompactService under the real invariants plugin', () => {
    session.append('turn/start', { turn, trigger: { kind: 'message', source: { kind: 'user' } } })
    session.append('step/start', { turn, step: 1 })
    session.append('user/message', { content: [{ type: 'text', text: `turn ${turn} user.${LONG_FIXTURE_TEXT}` }], source: { kind: 'user' } }, { surfaceOp: 'append' })
-    session.append('assistant/message', { turn, step: 1, content: [{ type: 'text', text: `turn ${turn} assistant.${LONG_FIXTURE_TEXT}` }] }, { surfaceOp: 'append' })
+    session.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' }, turn, step: 1, content: [{ type: 'text', text: `turn ${turn} assistant.${LONG_FIXTURE_TEXT}` }] }, { surfaceOp: 'append' })
    session.append('step/end', { turn, step: 1 })
    session.append('turn/end', { turn, reason: { kind: 'completed' } })
  }
--- a/packages/compact/compact-basic/tests/compact-loop-repro.spec.ts
+++ b/packages/compact/compact-basic/tests/compact-loop-repro.spec.ts
@@ -41,8 +41,8 @@ class ReproCompactService extends BasicCompactService {
    return blocks.length * TOKENS_PER_BLOCK
  }

-  override async summarize(): Promise<{ summary: ContentBlock[]; model: string }> {
-    return { summary: [{ type: 'text', text: 'CHECKPOINT SUMMARY' }], model: 'stub' }
+  override async summarize(): Promise<{ summary: ContentBlock[]; provider: string; model: string }> {
+    return { summary: [{ type: 'text', text: 'CHECKPOINT SUMMARY' }], provider: 'mock', model: 'stub' }
  }
 }

@@ -97,6 +97,7 @@ async function harness(toolSteps: number): Promise<{ ctx: Context; compact: Repr
    contextWindow: 64,
    thresholdRatio: 0.5,
    retainTokens: 20,
+    summarizationProvider: '',
    summarizationModel: '',
    maxTokens: 8192,
    compactionRetries: 1,
@@ -119,7 +120,7 @@ describe('CBR-001: a real-loop checkpoint is a valid boundary on both sides', ()
  it('the head checkpoint the loop lands is a balanced cut on both sides', async () => {
    const { ctx } = await harness(8)
    try {
-      const agent = ctx.agentLoop.create(AgentId('repro'), { model: 'mock' })
+      const agent = ctx.agentLoop.create(AgentId('repro'), { provider: 'mock', model: 'mock' })
      agent.send([{ type: 'text', text: 'do a long multi-step task' }])
      await waitForIdle(ctx, agent)

--- a/packages/compact/compact/README.md
+++ b/packages/compact/compact/README.md
@@ -29,7 +29,7 @@ Both methods are **abstract** — the backend owns the entire strategy (token es

 1. appends `compact/start` (log-only) — acquires the lock,
 2. summarizes the range,
-3. appends `compact/summary` (log-only) — provenance: summary, range, shadowed seqs, token count,
+3. appends `compact/summary` (log-only) — provenance: summary, range, shadowed seqs, token count, and provider/model call envelope,
 4. appends a single `user/message` with `surfaceOp: { op: 'replace', start, end }` carrying the summary — **the only surface mutation**,
 5. appends `compact/end` (log-only) — releases the lock.

--- a/packages/compact/compact/src/types.ts
+++ b/packages/compact/compact/src/types.ts
@@ -32,6 +32,8 @@ declare module '@deepseek-ai/dsh-session' {
      shadowedRange: { start: number; end: number }
      shadowedSeqs: number[]
      shadowedTokenCount: number
+      /** The provider route that wrote the summary. */
+      provider: string
      /**
       * The model that wrote the summary — the summarize call's envelope,
       * reported by the backend that made the call, logged so the one-shot
--- a/packages/compact/compact/tests/compact.spec.ts
+++ b/packages/compact/compact/tests/compact.spec.ts
@@ -41,6 +41,7 @@ class StubCompactService extends CompactService {
      shadowedRange: { start, end },
      shadowedSeqs: [],
      shadowedTokenCount: 0,
+      provider: 'mock',
      model: 'stub',
    })
    const endEvent = session.append('compact/end', { turn: 0 })
--- a/packages/compact/compact/tests/render.spec.ts
+++ b/packages/compact/compact/tests/render.spec.ts
@@ -54,7 +54,7 @@ describe('renderTranscript', () => {
      content: [{ type: 'text', text: 'fix the bug' }],
      source: { kind: 'user' },
    }, { surfaceOp: 'append' })
-    const assistant = s.append('assistant/message', {
+    const assistant = s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 0, step: 0,
      content: [{ type: 'text', text: 'looking' }],
    }, { surfaceOp: 'append' })
@@ -111,7 +111,7 @@ describe('renderTranscript', () => {
      content: [{ type: 'text', text: '' }],
      source: { kind: 'user' },
    }, { surfaceOp: 'append' })
-    const emptyAssistant = s.append('assistant/message', {
+    const emptyAssistant = s.append('assistant/message', { provenance: { provider: 'mock', model: 'mock' },
      turn: 0, step: 0,
      content: [{ type: 'text', text: '' }],
    }, { surfaceOp: 'append' })
--- a/packages/cordis/tool-cordis/src/api-catalog.ts
+++ b/packages/cordis/tool-cordis/src/api-catalog.ts
@@ -129,8 +129,8 @@ export const SERVICE_API: readonly ServiceApiEntry[] = [
    key: 'llm',
    summary: 'The abstract `llm` service: an adapter registry plus a streaming model-call surface, interceptable via the `llm/stream` waterfall.',
    methods: [
-      'registerAdapter(models: string[], adapter: LlmAdapter): () => void',
-      'models(): string[]',
+      'registerAdapter(providers: string[], adapter: LlmAdapter): () => void',
+      'providers(): string[]',
      'stream(options: GenerateOptions): AsyncIterable<StreamChunk>',
    ],
  },
@@ -504,7 +504,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'AgentOptions',
-    declaration: 'export interface AgentOptions {\n    model?: string;\n}',
+    declaration: 'export interface AgentOptions {\n    provider?: string;\n    model?: string;\n}',
  },
  {
    name: 'AgentStatus',
@@ -546,6 +546,10 @@ export const TYPE_API: readonly TypeApiEntry[] = [
    name: 'AssembledSection',
    declaration: 'export interface AssembledSection {\n    name: string;\n    order: number;\n    text: string;\n}',
  },
+  {
+    name: 'AssistantProvenance',
+    declaration: 'export interface AssistantProvenance {\n    provider: string;\n    model: string;\n    replayState?: unknown;\n}',
+  },
  {
    name: 'BashExecRequest',
    declaration: 'export interface BashExecRequest {\n    command: string;\n    workdir?: string | undefined;\n    timeoutMs?: number | undefined;\n    signal?: AbortSignal | undefined;\n    stdin?: string | undefined;\n    env?: Record<string, string> | undefined;\n    owner?: OwnerToken | undefined;\n    sandboxMode?: SandboxMode | undefined;\n}',
@@ -712,7 +716,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'GenerateOptions',
-    declaration: 'export interface GenerateOptions {\n    model: string;\n    messages: Message[];\n    system?: string;\n    tools?: ToolSchema[];\n    temperature?: number;\n    maxTokens?: number;\n    stop?: string[];\n    signal?: AbortSignal;\n    sessionId?: Branded<\'SessionId\'>;\n}',
+    declaration: 'export interface GenerateOptions {\n    provider: string;\n    model: string;\n    messages: Message[];\n    system?: string;\n    tools?: ToolSchema[];\n    temperature?: number;\n    maxTokens?: number;\n    stop?: string[];\n    signal?: AbortSignal;\n    sessionId?: Branded<\'SessionId\'>;\n}',
  },
  {
    name: 'GenericCallView',
@@ -728,7 +732,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'Message',
-    declaration: 'export interface Message {\n    role: \'system\' | \'user\' | \'assistant\';\n    content: ContentBlock[];\n}',
+    declaration: 'export interface Message {\n    role: \'system\' | \'user\' | \'assistant\';\n    content: ContentBlock[];\n    provenance?: AssistantProvenance;\n}',
  },
  {
    name: 'MessageSource',
@@ -784,7 +788,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'SessionEventMap',
-    declaration: 'export interface SessionEventMap {\n    \'turn/start\': {\n        turn: number;\n        trigger: TurnTrigger;\n    };\n    \'turn/end\': {\n        turn: number;\n        reason: TurnEndReason;\n    };\n    \'step/start\': {\n        turn: number;\n        step: number;\n    };\n    \'step/end\': {\n        turn: number;\n        step: number;\n    };\n    \'user/message\': {\n        content: ContentBlock[];\n        source: MessageSource;\n    };\n    \'prompt/blocked\': {\n        content: ContentBlock[];\n        source: MessageSource;\n        reason: string;\n    };\n    \'context/message\': {\n        content: ContentBlock[];\n        source: MessageSource;\n    };\n    \'assistant/chunk\': {\n        turn: number;\n        step: number;\n        chunk: StreamChunk;\n    };\n    \'assistant/message\': {\n        turn: number;\n        step: number;\n        content: ContentBlock[];\n        usage?: TokenUsage;\n    };\n    \'tool/call\': {\n        turn: number;\n        step: number;\n        callId: CallId;\n        name: string;\n        arguments: string;\n    };\n    \'tool/result\': {\n        turn: number;\n        step: number;\n        callId: CallId;\n        content: ContentBlock[];\n        isError: boolean;\n        error?: {\n            name: string;\n            code: string;\n        };\n        meta?: unknown;\n    };\n    \'steering/message\': {\n        turn: number;\n        content: ContentBlock[];\n        source: MessageSource;\n    };\n    \'todo/write\': {\n        todos: TodoItem[];\n    };\n    \'request/header\': {\n        header: E /* …truncated — full shape in source */',
+    declaration: 'export interface SessionEventMap {\n    \'turn/start\': {\n        turn: number;\n        trigger: TurnTrigger;\n    };\n    \'turn/end\': {\n        turn: number;\n        reason: TurnEndReason;\n    };\n    \'step/start\': {\n        turn: number;\n        step: number;\n    };\n    \'step/end\': {\n        turn: number;\n        step: number;\n    };\n    \'user/message\': {\n        content: ContentBlock[];\n        source: MessageSource;\n    };\n    \'prompt/blocked\': {\n        content: ContentBlock[];\n        source: MessageSource;\n        reason: string;\n    };\n    \'context/message\': {\n        content: ContentBlock[];\n        source: MessageSource;\n    };\n    \'assistant/chunk\': {\n        turn: number;\n        step: number;\n        chunk: StreamChunk;\n    };\n    \'assistant/message\': {\n        turn: number;\n        step: number;\n        content: ContentBlock[];\n        provenance: AssistantProvenance;\n        usage?: TokenUsage;\n    };\n    \'tool/call\': {\n        turn: number;\n        step: number;\n        callId: CallId;\n        name: string;\n        arguments: string;\n    };\n    \'tool/result\': {\n        turn: number;\n        step: number;\n        callId: CallId;\n        content: ContentBlock[];\n        isError: boolean;\n        error?: {\n            name: string;\n            code: string;\n        };\n        meta?: unknown;\n    };\n    \'steering/message\': {\n        turn: number;\n        content: ContentBlock[];\n        source: MessageSource;\n    };\n    \'todo/write\': {\n        todos: TodoItem[];\n    };\n /* …truncated — full shape in source */',
  },
  {
    name: 'SessionEventType',
@@ -836,7 +840,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'StreamChunk',
-    declaration: 'export type StreamChunk = {\n    type: \'block-start\';\n    index: number;\n    blockType: ContentBlockType;\n} | {\n    type: \'text-delta\';\n    index: number;\n    text: string;\n} | {\n    type: \'reasoning-delta\';\n    index: number;\n    text: string;\n} | {\n    type: \'tool-call-delta\';\n    index: number;\n    id: CallId;\n    name?: string;\n    argumentsDelta: string;\n} | {\n    type: \'block-end\';\n    index: number;\n    block: ContentBlock;\n} | {\n    type: \'usage\';\n    usage: TokenUsage;\n} | {\n    type: \'finish\';\n    reason: FinishReason;\n};',
+    declaration: 'export type StreamChunk = {\n    type: \'block-start\';\n    index: number;\n    blockType: ContentBlockType;\n} | {\n    type: \'text-delta\';\n    index: number;\n    text: string;\n} | {\n    type: \'reasoning-delta\';\n    index: number;\n    text: string;\n} | {\n    type: \'tool-call-delta\';\n    index: number;\n    id: CallId;\n    name?: string;\n    argumentsDelta: string;\n} | {\n    type: \'block-end\';\n    index: number;\n    block: ContentBlock;\n} | {\n    type: \'usage\';\n    usage: TokenUsage;\n} | {\n    type: \'finish\';\n    reason: FinishReason;\n    replayState?: unknown;\n};',
  },
  {
    name: 'StructuredOutputSchema',
@@ -1040,7 +1044,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
  },
  {
    name: 'WorkflowPhase',
-    declaration: 'export interface WorkflowPhase {\n    title: string;\n    detail?: string;\n    model?: string;\n}',
+    declaration: 'export interface WorkflowPhase {\n    title: string;\n    detail?: string;\n    provider?: string;\n    model?: string;\n}',
  },
  {
    name: 'WorkflowResult',
--- a/packages/cordis/tool-cordis/tests/integration.spec.ts
+++ b/packages/cordis/tool-cordis/tests/integration.spec.ts
@@ -51,7 +51,7 @@ describe('cordis tools through the agent loop', () => {
      textResponse('Done.'),
    ])
    const ctx = await harness(adapter)
-    const agent = ctx.agentLoop.create(AgentId('it-cordis'), { model: 'mock' })
+    const agent = ctx.agentLoop.create(AgentId('it-cordis'), { provider: 'mock', model: 'mock' })

    agent.send([{ type: 'text', text: 'give yourself reverse_text, use it, clean up' }])
    await waitForIdle(ctx, agent)
--- a/packages/core/agent-core/tests/agent-core.spec.ts
+++ b/packages/core/agent-core/tests/agent-core.spec.ts
@@ -108,7 +108,7 @@ describe('dsh-agent-core bundle', () => {

  it('forwards a pre-created agent to the loop and the persona to system-prompt', async () => {
    const ctx = await mount({
-      agents: [{ id: AgentId('main'), model: 'mock' }],
+      agents: [{ id: AgentId('main'), provider: 'mock', model: 'mock' }],
      persona: 'You are main.',
    })
    expect(ctx.get('agents')?.get(AgentId('main'))).toBeDefined()
--- a/packages/core/agent-loop/README.md
+++ b/packages/core/agent-loop/README.md
@@ -33,6 +33,7 @@ The config-driven `ctx.agentLoop.create()` path keeps its agent owned by the loo
 interface Config {
  agents: Array<{
    id: string                 // required
+    provider?: string
    model?: string
    resumeSessionId?: string   // load this persisted session instead of creating one
    cwd?: string               // optional workspace cwd for the fresh session
@@ -40,7 +41,7 @@ interface Config {
 }
 ```

-Agents listed in config are auto-created at startup. `cwd` applies only to fresh config-created sessions; `resumeSessionId` keeps the persisted session header. Config agents have no per-agent persona field: they use `dsh-system-prompt`'s deployment default, while programmatic factory callers can register an agent-scoped `deployment:persona` shadow in `setup`. The plugin registers the built-in `model`/`cwd` prompt variables on `ctx.systemPrompt`, resolved per step from `assembleContextFor(agent)` — the helper couples the typed agent with its matching scope selector. These are runtime facts of the agents THIS loop drives, unlike the `harness:identity` and default `deployment:persona` sections, which live on `dsh-system-prompt` so they survive a swapped loop plugin.
+Agents listed in config are auto-created at startup. A model call requires both `provider` and `model`; a request-waterfall listener may supply the pair before dispatch when they are absent from creation options. `cwd` applies only to fresh config-created sessions; `resumeSessionId` keeps the persisted session header. Config agents have no per-agent persona field: they use `dsh-system-prompt`'s deployment default, while programmatic factory callers can register an agent-scoped `deployment:persona` shadow in `setup`. The plugin registers the built-in `provider`/`model`/`cwd` prompt variables on `ctx.systemPrompt`, resolved per step from `assembleContextFor(agent)` — the helper couples the typed agent with its matching scope selector. These are runtime facts of the agents THIS loop drives, unlike the `harness:identity` and default `deployment:persona` sections, which live on `dsh-system-prompt` so they survive a swapped loop plugin.

 ### Exported concrete class

--- a/Show More
+++ b/Show More