Merge remote-tracking branch 'origin/master' into scoped-layers-store

# Conflicts:
#	docs/architecture.md

docs/core-data-structures/core.md

@@ -23,6 +23,7 @@ Everything else is documented on a **sub-page**, not here. The rule that draws t
 | [session.md](session.md) | the full `SessionEventMap` variant catalog, `TurnTrigger`/`TurnEndReason`, `deriveMessages()`, the turn-enclosure invariant |
 | [persistence.md](persistence.md) | the durability seam: `SessionPersistence`, JSONL + SQLite backends, `session/flush`, crash recovery, `SessionHeader` |
 | [session-query.md](session-query.md) | logical records, bounded exact-event reads, and relationship traces |
+| [session-title.md](session-title.md) | durable title snapshots, source provenance, and the asynchronous provider contract |
 | [system-prompt.md](system-prompt.md) | per-assembly context, tool-provider results, prompt sections, and cooperative assembly |
 | [tools.md](tools.md) | `ToolDefinition` full fields, the schema DSL, `ToolExecution`/`ToolResult`, tool-presentation UI types, and the guarded execution pipeline |
 | [user-interaction.md](user-interaction.md) | the UI-backed human question/answer seam: `AskUserQuestionRequest`, answer/options vocabulary, provider API, error taxonomy |
@@ -279,7 +280,7 @@ The model-facing `ToolSchema` is the wire shape; the registered `ToolDefinition`
 
 The loop builds each request from logged state. `EpochHeader` records call config, rendered prompt, authoritative returned tool order (configured by `toolOrder`, or lexicographic when unset), and session prefix through full `request/header` snapshots. Together with derived history, this makes the request reconstructable from the session log. See [session.md](session.md#the-request-header-event-requestheader) and the [reconstructability Agent Note](../../.agents/notes/implemented/architecture/2026-07-05-reconstructable-requests.md).
 
-`agent/request` receives a frozen call-config seed and may return a replacement to switch provider, model, or sampling. `agent/session-prefix` composes request-only prefix messages once per loop instance, and the header records the exact result used. Requests reaching `llm/stream` are deep-frozen, so mutation throws.
+`agent/request` receives a frozen call-config seed and may return a replacement to switch provider, model, or sampling. `agent/session-prefix` composes request-only prefix messages once per loop instance, and the header records the exact result used. Requests reaching `llm/stream` are deep-frozen, so mutation throws, and carry a process-local loop identity so observers do not confuse separately logged frozen auxiliary calls with conversation requests.
 
 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.
 

docs/core-data-structures/session-title.md

@@ -0,0 +1,140 @@
+# Session Titles
+
+Durable latest-wins title state and the optional asynchronous provider vocabulary owned by [`@deepseek-ai/dsh-session-title`](../../packages/session-title/session-title). The shared LLM helper owns the exact auxiliary request record. Package READMEs own timing, fallback, failure, and fork behavior; the generated [persistence catalog](../persistence-catalog.md) owns the complete event declarations.
+
+Sources: [`packages/session-title/session-title/src/index.ts`](../../packages/session-title/session-title/src/index.ts), [`packages/session-title/session-title-llm/src/index.ts`](../../packages/session-title/session-title-llm/src/index.ts)
+
+## Durable title state
+
+`SessionTitleProviderId` is recorded for provider-produced revisions. `SessionTitleEventData` carries exact human-message provenance, while `SessionTitleSnapshot` adds the durable event envelope facts selected by `foldSessionTitle()`.
+
+```ts type-equiv
+/** Identifies one session-title provider registration. */
+type SessionTitleProviderId = Branded<'SessionTitleProviderId'>
+```
+
+```ts type-equiv
+/** Exact auxiliary model route that produced a title. */
+interface SessionTitleModelProvenance {
+  /** Registered LLM provider route. */
+  readonly provider: string
+  /** Provider model id. */
+  readonly model: string
+}
+```
+
+```ts type-equiv
+/** Durable ownership record for an accepted session title. */
+type SessionTitleSource =
+  | { readonly kind: 'fallback' }
+  | {
+    readonly kind: 'provider'
+    readonly provider: SessionTitleProviderId
+    readonly model?: SessionTitleModelProvenance
+  }
+```
+
+```ts type-equiv
+/** Payload of the log-only `session/title` event. */
+interface SessionTitleEventData {
+  /** Normalized non-empty title text. */
+  readonly title: string
+  /** Exact human `user/message` seqs used to derive this title. */
+  readonly messageSeqs: number[]
+  /** Built-in fallback or registered-provider provenance. */
+  readonly source: SessionTitleSource
+}
+```
+
+```ts type-equiv
+/** Latest folded title plus the title event's durable envelope facts. */
+interface SessionTitleSnapshot extends SessionTitleEventData {
+  /** Seq of the latest `session/title` event. */
+  readonly eventSeq: number
+  /** Timestamp of the latest `session/title` event. */
+  readonly updatedAt: number
+}
+```
+
+## Auxiliary request record
+
+The shared LLM helper records each validated, dispatchable title request before calling the model. The payload reproduces the model-visible system and message input, routing, output limit, provider ownership, and source-message attribution even when generation later fails.
+
+```ts type-equiv
+/** Exact model-visible request recorded before one auxiliary title dispatch. */
+interface SessionTitleLlmRequestEventData {
+  /** Registered title-provider identity responsible for the request. */
+  readonly titleProvider: SessionTitleProviderId
+  /** Exact human `user/message` seqs represented in `messages`. */
+  readonly messageSeqs: number[]
+  /** Exact auxiliary LLM route. */
+  readonly route: SessionTitleModelProvenance
+  /** Exact auxiliary system prompt. */
+  readonly system: string
+  /** Exact auxiliary message list. */
+  readonly messages: Message[]
+  /** Exact auxiliary output-token cap. */
+  readonly maxTokens: number
+}
+```
+
+## Provider input and output
+
+The service snapshots eligible messages through one revision. A provider returns only seqs from that request; service-owned acceptance verifies ordering, normalizes the title, enforces the byte limit, and appends provenance.
+
+```ts type-equiv
+/** One eligible human text message exposed to title providers. */
+interface SessionTitleUserMessage {
+  /** Source `user/message` event seq. */
+  readonly seq: number
+  /** Exact concatenated text-block content. */
+  readonly text: string
+}
+```
+
+```ts type-equiv
+/** Automatic generation cadence owned by a registered provider. */
+type SessionTitleAutomaticMode = 'first-message' | 'all-user-messages'
+```
+
+```ts type-equiv
+/** Immutable input supplied to one title-provider call. */
+interface SessionTitleProviderRequest {
+  /** Live session being titled. */
+  readonly session: Session
+  /** All eligible human messages through this generation revision. */
+  readonly messages: readonly SessionTitleUserMessage[]
+  /** Exact current logged main-request route, when one has been recorded. */
+  readonly route?: SessionTitleModelProvenance
+  /** Cancellation for supersession, disposal, timeout composition, or the explicit caller. */
+  readonly signal: AbortSignal
+}
+```
+
+```ts type-equiv
+/** Provider output before service-owned normalization and durable acceptance. */
+interface SessionTitleProviderResult {
+  /** Proposed title text. */
+  readonly title: string
+  /** Exact seqs from `request.messages` used by this result. */
+  readonly messageSeqs: readonly number[]
+  /** Auxiliary LLM route, when generation used a model. */
+  readonly model?: SessionTitleModelProvenance
+}
+```
+
+```ts type-equiv
+/** One optional asynchronous title implementation registered with the service. */
+interface SessionTitleProvider {
+  /** Stable provider identity recorded in title provenance. */
+  readonly id: SessionTitleProviderId
+  /** When new human prompts start automatic generation. */
+  readonly automatic: SessionTitleAutomaticMode
+  /**
+   * Produce one title revision.
+   * @param request - message snapshot, current route, session, and cancellation.
+   * @returns proposed title plus exact input seqs and optional model provenance.
+   */
+  generate(request: SessionTitleProviderRequest): Promise<SessionTitleProviderResult>
+}
+```

docs/core-data-structures/session.md

@@ -94,6 +94,20 @@ interface SessionEventMap {
 }
 ```
 
+### `OutOfBandSessionEventMap` — narrow late-append opt-in
+
+`SessionEventMap` membership alone does not authorize an event outside the agent loop's ordinary lifecycle. An event owner declaration-merges the same key into this empty marker map before `ctx.sessions.appendOutOfBand()` accepts it; the derived type additionally excludes every surface event. An accepted update joins an open turn or receives a balanced, flushed zero-step turn.
+
+```ts type-equiv
+/**
+ * Marker map for plugin-owned log-only events accepted by
+ * `SessionStore.appendOutOfBand()`. A plugin extends this map with the same key
+ * it adds to {@link SessionEventMap}; surface and lifecycle events stay
+ * ineligible unless their owner explicitly opts them into this narrow seam.
+ */
+interface OutOfBandSessionEventMap {}
+```
+
 ### `TodoItem` — one todo-list entry
 
 The unit of the `todo/write` event's whole-list snapshot. Deliberately minimal — a `content` line and a three-state `status` (no id, priority, or `activeForm`): the list is replaced wholesale on every write, so entries need no stable identity, and the status triple is exactly the ACP `PlanEntryStatus`, so a UI bridge can map a todo list onto an ACP `plan` 1:1 (synthesizing the priority ACP additionally requires). See the [todo_write Agent Note](../../.agents/notes/implemented/feature/2026-06-29-todo-write-tool.md).
@@ -504,7 +518,7 @@ interface TurnEndReasonMap {
 
 ## The turn-enclosure invariant
 
-Every session event lives **inside** a turn (between a `turn/start` and its `turn/end`). The loop appends queued `user/message` events *after* `turn/start`, and an idle `agent.inject()` wraps its `context/message` in a one-shot `injection` turn. This makes the turn the single durability/replay boundary: a backend can treat anything after the last `turn/end` as an interrupted-crash tail without risking the loss of legitimately-recorded between-turn context. The optional `dsh-session/invariant` companion enforces it in dev through `ctx.invariants` (a message event outside an open turn throws). See [the turn-enclosure invariant Agent Note](../../.agents/notes/implemented/architecture/2026-06-15-turn-enclosure-invariant.md).
+Every session event lives **inside** a turn (between a `turn/start` and its `turn/end`). The loop appends queued `user/message` events *after* `turn/start`, an idle `agent.inject()` wraps its `context/message` in a one-shot `injection` turn, and `appendOutOfBand()` similarly wraps an eligible log-only event when no turn is open. This makes the turn the single durability/replay boundary: a backend can treat anything after the last `turn/end` as an interrupted-crash tail without risking the loss of legitimately-recorded between-turn context. The optional `dsh-session/invariant` companion enforces it in dev through `ctx.invariants` (a message event outside an open turn throws). See [the turn-enclosure invariant Agent Note](../../.agents/notes/implemented/architecture/2026-06-15-turn-enclosure-invariant.md).
 
 ## Plugin-contributed log-only events