Merge latest origin/master into feat/tui-package

Master advanced with PR #375's documentation-only simplification RFCs while the TUI merge was validating. Incorporate that exact head as a merge commit so PR #363 retains current-base ancestry without rewriting its reviewed history; no TUI behavior or generated terminal artifact changes are involved.

docs/rfc/INDEX.md

@@ -21,6 +21,9 @@ Generated by `pnpm run gen-rfc-index` from the RFC tree — never edit by hand;
 | Title | First proposed |
 |---|---|
 | [Prune dead public and result surface](proposed/simplification/2026-07-04-prune-dead-core-spine-surface.md) | 2026-07-04 |
+| [Make JSON-RPC completion and transport directional](proposed/simplification/2026-07-19-make-jsonrpc-directional.md) | 2026-07-19 |
+| [Retire the standalone subagent mock package](proposed/simplification/2026-07-19-retire-subagent-mock-package.md) | 2026-07-19 |
+| [Use one surface manager per session](proposed/simplification/2026-07-19-use-one-session-surface-manager.md) | 2026-07-19 |
 
 ### Architecture
 
@@ -231,6 +234,7 @@ Generated by `pnpm run gen-rfc-index` from the RFC tree — never edit by hand;
 | [Prune the unimplemented subagent seam vocabulary](rejected/simplification/2026-07-04-prune-unimplemented-subagent-vocabulary.md) | 2026-07-04 |
 | [Collapse workflows to the exercised foreground core](rejected/simplification/2026-07-12-collapse-workflow-to-foreground-core.md) | 2026-07-12 |
 | [Prune unused skill registry surface](rejected/simplification/2026-07-12-prune-unused-skill-registry-surface.md) | 2026-07-12 |
+| [Fold the single compaction backend into its service package](rejected/simplification/2026-07-19-fold-compaction-package-split.md) | 2026-07-19 |
 
 ### Architecture
 

docs/rfc/proposed/simplification/2026-07-04-prune-dead-core-spine-surface.md

@@ -25,6 +25,7 @@ The production corpus is `packages/*/*/src`, example sources/config, and runtime
 | `CompactionResult.startSeq`, `summarySeq`, `endSeq`, and `summary` | The production consumer reads only shadowed range/seq/token accounting; the durable log owns summary and event identity. | Remove the four result echoes while keeping both shared transcript renderers. |
 | `BasicCompactService` estimation/summarization visibility | No outside production caller invokes the five methods; the implemented RFC names only `estimateContentTokens()` and `summarize()` as subclass hooks. | Make those two `protected` and the three orchestration-only estimators private. |
 | `CodeLogEntry.source`/`level` and `RunCodeMeta.dispatches` | Every production consumer maps logs to text; no presenter/model path reads the other fields or the persisted dispatch count. | Make code-runtime logs strings (or text-only entries) and remove result-meta dispatch plumbing; keep the local counter that mints deterministic dispatch ids. |
+| `CodeRuntime.language` and `CodeRuntime.isolation` | The worker backend supplies the only production values, while Code Mode and every other production caller invoke only `run()`. | Remove the unread descriptors while preserving the worker's language, isolation, budgets, cancellation, and disposal behavior. |
 | `ToolNotFoundError.toolName`, `SystemPrompt.config`, and `BashTask.command` | Each stored public value has no production reader. | Drop the unread field while retaining error messages, resolved configuration behavior, and task lifecycle. |
 | Backend package-root implementation helpers | The exact inventory below is called only through relative same-package imports. Production namespace imports mount the retained plugin contract without reading these properties; named root consumers are tests. | Retain each adapter/provider/service and its config/error contract; stop exporting the listed helper functions/constants at package roots. |
 | Consumer package-root implementation helpers | The exact inventory below has only same-package production callers. Production namespace imports mount plugin contracts without reading helper properties; named root consumers are tests. | Retain plugin contracts and stable error codes; move tests to package-local modules or public behavior and stop exporting the listed helpers at package roots. |

docs/rfc/proposed/simplification/2026-07-19-make-jsonrpc-directional.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write
+2026-07-19-make-jsonrpc-directional.md: 2a9579c53c111887e9d93cf02cc832304a496795
+2026-07-19-make-jsonrpc-directional.zh.md: 4f3793f1b4de3b4f69c4219c10fe5b3b360c8692

docs/rfc/proposed/simplification/2026-07-19-make-jsonrpc-directional.md

@@ -0,0 +1,46 @@
+# RFC: Make JSON-RPC completion and transport directional
+
+Status: proposed
+
+English | [中文](2026-07-19-make-jsonrpc-directional.zh.md)
+
+## Problem
+
+The JSON-RPC bridge models both endpoints as symmetric peers although the shipped protocol is directional. The TypeScript server accepts requests and emits responses or notifications, but its transport also implements unused outbound requests and inbound notification dispatch. The Python SDK sends requests and receives responses or notifications, but it also queues unused inbound server requests and exposes response helpers.
+
+`session/prompt` also reports one settled turn through two protocol shapes. The server emits `session.finished` and then returns the constant `{ accepted: true }`; the Python SDK discards that response and waits for the notification to recover the status. Because the response is written only after the handler returns, the notification necessarily precedes the constant response on the same stream.
+
+The unused halves add pending-request maps, generated IDs, request queues, close-time rejection paths, response helpers, and a second completion waiter without serving a production caller.
+
+## Proposal
+
+Specialize each endpoint to its actual role. The TypeScript transport will retain inbound requests, outbound responses, and outbound notifications. The Python client will retain outbound requests and inbound responses or notifications. Delete the opposite-direction request machinery from each side.
+
+Return the settled outcome directly from `session/prompt` as `{ status, reason }` after `agent.whenIdle()`. Delete `session.finished`, the constant acceptance response, and the Python post-response completion loop. `session.event` and subagent notifications still stream before the response, and durable session events remain the source for final-response reconstruction.
+
+## Implementation plan
+
+1. In `packages/ui/jsonrpc/src/server.ts`, replace `SessionPromptResult.accepted` with `status: 'ok' | 'error' | 'aborted'` and the captured `TurnEndReason`. `HarnessSdkServer.prompt()` will return `completed` as `ok`, `aborted` as `aborted`, and every other current or merge-extensible reason as `error`; reaching idle without a `turn/end` remains an invariant error. Remove only `session.finished`, leaving `session.event`, `subagent.started`, and `subagent.finished` unchanged.
+2. In `packages/ui/jsonrpc/src/transport.ts`, replace `JsonRpcTransportPeer` with a server-side notification surface and retain `onRequest()`, `notify()`, `start()`, `flush()`, and `close()`. Remove generated request IDs, the pending-response map, outbound `request()`, inbound response and notification dispatch, and close-time pending-request rejection. Incoming response- and notification-shaped frames will be ignored, while request result, method-not-found, and handler-error responses retain their current behavior and remain ordered after notifications emitted by the awaited handler.
+3. In `python/sdk/src/deepseek_harness/client.py`, `models.py`, and `__init__.py`, remove `IncomingRequest`, `_requests`, `notify()`, `next_request()`, `respond()`, and `respond_error()`. Add a public validated `SessionPromptResponse` carrying status and reason, return it from `session_prompt()`, and keep an explicit reader guard that ignores unexpected server-request frames instead of allowing them to match a response waiter.
+4. In `python/sdk/src/deepseek_harness/api.py`, build `TurnResult.status` and a new `TurnResult.reason` from `SessionPromptResponse`, then delete the `session.finished` branch and second completion loop. Keep the subscription open during the request and preserve `_request_raw()`'s final notification drain so the last `turn/end` event and any subagent notification written before the response are collected before `Session.run()` reconstructs the final assistant message.
+5. Replace the symmetric transport-pair cases in `packages/ui/jsonrpc/tests/transport.spec.ts` with raw client-input/server-output coverage, and update `server.spec.ts`, `plugin-apply.spec.ts`, and `built-scope-carrier.e2e.ts` for direct outcomes, ordering, overlap, shutdown, and the narrowed fake. Update `python/sdk/tests/test_client.py` for response-based settlement, unexpected-request-frame handling, callback and concurrency behavior, and the removed public helpers. Update the JSON-RPC and bilingual Python SDK READMEs, export JSDoc and declarations, `scripts/smoke-python-runtime.py`, and the Python single-executable snapshot.
+
+## Alternatives considered
+
+**Keep a generic symmetric JSON-RPC peer for future methods.** Server-initiated requests may eventually support interactive permissions, but no typed method or production consumer exists. The pre-release protocol can add the smallest required direction when that feature is designed instead of carrying an unexercised peer today.
+
+**Keep `session.finished` for streaming clients.** Turn settlement is not incremental data: the request response already marks the same boundary and follows all earlier notifications on the ordered stream. A second terminal notification creates two representations that clients must reconcile.
+
+## Acceptance criteria
+
+- The TypeScript endpoint cannot originate requests or consume notifications.
+- The Python endpoint cannot originate notifications or consume server requests.
+- `session/prompt` returns the authoritative `ok`, `error`, or `aborted` outcome and reason after turn settlement.
+- Session events and subagent lifecycle notifications emitted during the turn arrive before the response.
+- Same-session overlap rejection, framing, multibyte input, handler errors, flush, shutdown ordering, and final-response reconstruction retain their behavior.
+- TypeScript bridge tests, Python SDK tests, built JSON-RPC coverage, snapshots, and generated API documentation pass.
+
+## Risks
+
+This deliberately narrows the pre-release wire protocol. Raw clients listening only for `session.finished`, or embedders using the unused symmetric transport methods, must move to the prompt response. A future server-initiated request requires a new typed protocol addition rather than reusing generic dormant machinery.

docs/rfc/proposed/simplification/2026-07-19-make-jsonrpc-directional.zh.md

@@ -0,0 +1,46 @@
+# RFC: 让 JSON-RPC 完成结果与传输方向单一化
+
+Status: proposed
+
+[English](2026-07-19-make-jsonrpc-directional.md) | 中文
+
+## 问题
+
+JSON-RPC 桥接层把两个端点都建模为对称的对等端，但实际协议具有固定方向。TypeScript 服务端接收请求并发出响应或通知，其传输层却还实现了未使用的出站请求和入站通知分发。Python SDK 发送请求并接收响应或通知，却还会把未使用的服务端入站请求放入队列，并公开响应辅助方法。
+
+`session/prompt` 还会用两种协议结构报告同一个已结束轮次。服务端先发出 `session.finished`，再返回常量 `{ accepted: true }`；Python SDK 丢弃该响应，转而等待通知以取得状态。响应只有在处理函数返回后才会写入，因此在同一条有序流上，通知必然先于这个常量响应。
+
+这些未使用的双向能力引入了待处理请求表、生成 ID、请求队列、关闭时的拒绝路径、响应辅助方法和第二套完成等待逻辑，却没有任何生产调用方使用。
+
+## 提案
+
+按实际角色收窄两个端点。TypeScript 传输层只保留入站请求、出站响应和出站通知。Python 客户端只保留出站请求以及入站响应或通知。删除两侧与实际方向相反的请求机制。
+
+在 `agent.whenIdle()` 完成后，由 `session/prompt` 直接返回 `{ status, reason }` 作为轮次结果。删除 `session.finished`、常量接纳响应以及 Python 中响应后的完成等待循环。`session.event` 与 subagent 通知仍在响应前流式发出，持久会话事件仍是最终响应重建的真源。
+
+## 实施计划
+
+1. 在 `packages/ui/jsonrpc/src/server.ts` 中，用 `status: 'ok' | 'error' | 'aborted'` 和捕获的 `TurnEndReason` 替换 `SessionPromptResult.accepted`。`HarnessSdkServer.prompt()` 把 `completed` 映射为 `ok`，把 `aborted` 映射为 `aborted`，把其他当前或可合并扩展的原因映射为 `error`；进入空闲状态却没有 `turn/end` 仍视为不变量错误。只删除 `session.finished`，保持 `session.event`、`subagent.started` 和 `subagent.finished` 不变。
+2. 在 `packages/ui/jsonrpc/src/transport.ts` 中，用服务端通知接口替换 `JsonRpcTransportPeer`，并保留 `onRequest()`、`notify()`、`start()`、`flush()` 和 `close()`。删除生成的请求 ID、待处理响应表、出站 `request()`、入站响应与通知分发，以及关闭时对待处理请求的拒绝逻辑。入站响应结构和通知结构将被忽略；请求结果、方法不存在与处理器错误响应保持原有行为，并继续排在被等待处理器发出的通知之后。
+3. 在 `python/sdk/src/deepseek_harness/client.py`、`models.py` 和 `__init__.py` 中，删除 `IncomingRequest`、`_requests`、`notify()`、`next_request()`、`respond()` 和 `respond_error()`。新增公开且经过校验的 `SessionPromptResponse` 来携带状态与原因，由 `session_prompt()` 返回该对象，并保留明确的读取保护：忽略意外的服务端请求帧，避免它们命中响应等待器。
+4. 在 `python/sdk/src/deepseek_harness/api.py` 中，根据 `SessionPromptResponse` 构造 `TurnResult.status` 和新增的 `TurnResult.reason`，再删除 `session.finished` 分支与第二个完成循环。请求期间保持订阅打开，并保留 `_request_raw()` 最后的通知排空步骤，确保写在响应前的最后一条 `turn/end` 事件与任何 subagent 通知，都会在 `Session.run()` 重建最终助手消息之前被收集。
+5. 用原始客户端输入与服务端输出覆盖替换 `packages/ui/jsonrpc/tests/transport.spec.ts` 中的对称传输对用例，并更新 `server.spec.ts`、`plugin-apply.spec.ts` 和 `built-scope-carrier.e2e.ts`，覆盖直接结果、顺序、重叠、关闭和收窄后的伪实现。更新 `python/sdk/tests/test_client.py`，覆盖基于响应的结束流程、意外请求帧处理、回调与并发行为，以及已删除的公开辅助方法。同步更新 JSON-RPC README、双语 Python SDK README、导出 JSDoc 与声明、`scripts/smoke-python-runtime.py` 和 Python 单可执行文件快照。
+
+## 备选方案
+
+**为未来方法保留通用的对称 JSON-RPC 对等端。** 服务端发起的请求将来可能用于交互式权限，但当前没有类型化方法或生产消费方。该功能完成设计后，预发布协议可以增加所需的最小方向，无需提前保留未使用的对等端能力。
+
+**为流式客户端保留 `session.finished`。** 轮次结束不是增量数据：请求响应已经标识同一个边界，并且在有序流中位于先前所有通知之后。第二条终止通知会产生两种结果表示，迫使客户端进行协调。
+
+## 验收标准
+
+- TypeScript 端点无法发起请求，也不消费通知。
+- Python 端点无法发起通知，也不消费服务端请求。
+- 轮次结束后，`session/prompt` 返回权威的 `ok`、`error` 或 `aborted` 状态及其原因。
+- 轮次中发出的会话事件与 subagent 生命周期通知都先于响应到达。
+- 同一会话的重叠拒绝、分帧、多字节输入、处理器错误、flush、关闭顺序与最终响应重建保持原有行为。
+- TypeScript 桥接测试、Python SDK 测试、构建后 JSON-RPC 覆盖、快照和生成的 API 文档全部通过。
+
+## 风险
+
+本提案会刻意收窄预发布协议格式。仅监听 `session.finished` 的原始客户端，以及使用未使用对称传输方法的嵌入方，都必须改为读取请求响应。未来若需要服务端发起请求，应新增类型化协议，而不是复用休眠的通用机制。

docs/rfc/proposed/simplification/2026-07-19-retire-subagent-mock-package.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write
+2026-07-19-retire-subagent-mock-package.md: 2731d35448cbc4dc9db4c92579c35202a53eefdd
+2026-07-19-retire-subagent-mock-package.zh.md: 919c56502227157465277cc07c23fb7096763684

docs/rfc/proposed/simplification/2026-07-19-retire-subagent-mock-package.md

@@ -0,0 +1,35 @@
+# RFC: Retire the standalone subagent mock package
+
+Status: proposed
+
+English | [中文](2026-07-19-retire-subagent-mock-package.zh.md)
+
+## Problem
+
+`@deepseek-ai/dsh-subagent-mock` is a configurable test double packaged as a workspace plugin. Its only external consumers are the `tool-subagent` unit suite and the tool-catalog generator. No runtime package, example, snapshot configuration, or real provider loads it.
+
+That narrow fixture carries a manifest, exports, peer and development dependencies, project references, package README obligations, Loader composition tests, module-graph membership, and documentation-gate exceptions. The tool-catalog generator mounts it only to make the real subagent tool register its schema; it never executes a child.
+
+## Proposal
+
+Delete `packages/support/subagent-mock`. Move the scripted provider behavior actually used by `tool-subagent` into a package-local test fixture while continuing to exercise the real `SubagentService`, provider registry, and tool implementation.
+
+Have the tool-catalog generator register the minimal provider descriptor required before mounting `ToolSubagent`. Remove the package references, manifest dependency, graph node, README allowlists, and mock-specific Loader tests.
+
+## Alternatives considered
+
+**Keep a reusable mock package for future tests.** Reuse has not materialized outside one test file and one generator. A future second consumer can extract a fixture once its shared contract is known; packaging all configurable reply, cancellation, result, and Loader behavior today makes test infrastructure look like a supported backend.
+
+**Generate the subagent schema without mounting the real tool.** Hand-constructing or importing the schema would weaken the catalog's check that the production registry and tool composition expose the documented shape. The generator should keep mounting the real service and tool with only the child boundary replaced.
+
+## Acceptance criteria
+
+- `packages/support/subagent-mock` and every workspace, graph, dependency, and documentation entry for it are removed.
+- `tool-subagent` tests retain every scripted reply, structured-result, cancellation, foreground/background, and task-integration case they currently exercise through the real service and tool.
+- Tool-catalog generation mounts the production subagent registry and tool with a minimal local provider and produces a byte-identical catalog.
+- No runtime or example package gains a dependency on test-only fixtures.
+- Focused subagent tests, catalog and graph generation, module-graph verification, build, hygiene, and the full pre-push suite pass.
+
+## Risks
+
+Relocating the fixture could accidentally replace too much production composition with a stub. The local fixture must implement only the nondeterministic child boundary; capability checks, lifecycle, task handling, and tool output remain under production code. Mock Loader and HMR coverage can disappear because no deployed composition consumes the package afterward.

docs/rfc/proposed/simplification/2026-07-19-retire-subagent-mock-package.zh.md

@@ -0,0 +1,35 @@
+# RFC: 撤销独立的 subagent mock 包
+
+Status: proposed
+
+[English](2026-07-19-retire-subagent-mock-package.md) | 中文
+
+## 问题
+
+`@deepseek-ai/dsh-subagent-mock` 是一个以工作区插件形式发布的可配置测试替身。它仅有两个外部消费方：`tool-subagent` 单元测试和工具目录生成器。运行时包、示例、快照配置和真实提供方都不会加载它。
+
+这个用途狭窄的 fixture（测试前置数据）需要维护 manifest（元数据清单）、导出、对等依赖（peer dependency）与开发依赖、项目引用、包（package）README 契约、Loader 组合测试、模块图成员关系以及文档门禁例外。工具目录生成器挂载它，只是为了让真实 subagent 工具注册 schema；生成器从不执行子 agent。
+
+## 提案
+
+删除 `packages/support/subagent-mock`。把 `tool-subagent` 实际使用的脚本化提供方行为移入该包的本地测试 fixture，同时继续测试真实的 `SubagentService`、提供方注册表和工具实现。
+
+工具目录生成器在挂载 `ToolSubagent` 前，只注册所需的最小提供方描述。删除该包的项目引用、manifest 依赖、图节点、README 允许列表和 mock 专用 Loader 测试。
+
+## 备选方案
+
+**为未来测试保留可复用 mock 包。** 除一个测试文件和一个生成器外，复用需求并未出现。未来产生第二个消费方时，可以在共享契约明确后再提取 fixture；当前把所有可配置回复、取消、结果与 Loader 行为打包，会使测试基础设施看起来像受支持的后端。
+
+**不挂载真实工具，直接生成 subagent schema。** 手工构造或直接导入 schema，会削弱目录生成器对生产注册表与工具组合是否公开文档结构的校验。生成器应继续挂载真实服务与工具，只替换不确定的子 agent 边界。
+
+## 验收标准
+
+- 删除 `packages/support/subagent-mock`，并移除其全部工作区、图、依赖和文档条目。
+- `tool-subagent` 测试保留当前通过真实服务与工具覆盖的全部脚本化回复、结构化结果、取消、前台与后台运行以及任务集成用例。
+- 工具目录生成器使用最小本地提供方挂载生产 subagent 注册表与工具，并生成字节级一致的目录。
+- 运行时包与示例包都不会新增对测试专用 fixture 的依赖。
+- 聚焦 subagent 测试、目录与图生成、模块图校验、构建、hygiene 和完整 pre-push 门禁全部通过。
+
+## 风险
+
+迁移 fixture 时，可能会误将过多生产组合替换成测试替身。本地 fixture 只能实现不确定的 subagent 边界；能力检查、生命周期、任务处理与工具输出仍由生产代码负责。由于之后不再有部署组合消费该包，可以删除 mock 的 Loader 与 HMR 覆盖。

docs/rfc/proposed/simplification/2026-07-19-use-one-session-surface-manager.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write
+2026-07-19-use-one-session-surface-manager.md: 0e4fa14b21f5054e1ace425712506c5c060f2251
+2026-07-19-use-one-session-surface-manager.zh.md: 26126310eefaf56aa45efc428a54e65f0cf35947

docs/rfc/proposed/simplification/2026-07-19-use-one-session-surface-manager.md

@@ -0,0 +1,43 @@
+# RFC: Use one surface manager per session
+
+Status: proposed
+
+English | [中文](2026-07-19-use-one-session-surface-manager.zh.md)
+
+## Problem
+
+`Session` maintains two `SurfaceManager` instances over the same append-only event log. `surfaceValidator` eagerly validates seed and append candidates, while the lazy `_surface` independently folds committed events for `session.surface`, derived messages, compaction, and workspace context. Once the public surface is read, every later event advances duplicate node and replacement-generation state.
+
+The [session surface decision](../../implemented/architecture/2026-06-18-session-surface.md) calls for one ordered surface and one representation to validate. The second manager does not create an independent authority or protect a different failure boundary; it repeats the canonical fold and gives the two views a state-drift opportunity.
+
+## Proposal
+
+Keep one `SurfaceManager` per `Session`. Seed and append acceptance continue to call `validateNext()` before committing an event, and the public surface view reads `nodes` and `replaceGeneration` from that same manager.
+
+Expose only the readonly surface contract from `Session.surface`; candidate validation remains owned by `Session`. Retain `foldSurface()` as the detached full-log replay function used by offline validation and reconstruction.
+
+## Implementation plan
+
+1. In `packages/core/session/src/surface.ts`, export a structural `SessionSurface` contract containing only readonly `nodes` and `replaceGeneration`, and make `SurfaceManager` implement it. Re-export that type from `packages/core/session/src/index.ts` so `Session.surface` no longer exposes `validateNext()` through its declaration.
+2. In `Session`, replace `surfaceValidator` and lazy `_surface` with one eagerly constructed `surfaceManager`. Route seed and append validation through that manager and return it from `get surface(): SessionSurface`; `deriveMessages()` will read the same nodes and generation. `validateNext()` may synchronize already committed log entries, but it must only plan the uncommitted candidate. The candidate reaches manager state after `log.push()` and the next delta synchronization, so rejection by surface validation or pre-commit `internal/dispatch` cannot leave phantom state.
+3. Keep `foldSurface()` and the transition functions in `surface.ts` unchanged. Compile and exercise the direct consumers in `packages/compact/compact/src/tool-pairing.ts`, `packages/compact/compact-basic/src/region.ts`, and `packages/context/workspace-context/src/state.ts`; they continue to consume only nodes and replacement generation.
+4. Extend `packages/core/session/tests/surface.spec.ts` to read the public view before an invalid candidate, prove that nodes and generation remain at the accepted prefix after rejection, append a later valid event, and compare every resulting prefix with `foldSurface()`. Add an `internal/dispatch` veto case and a type-level `SessionSurface` assertion in `session.spec.ts`, while retaining the seeded replay, delta-growth, replacement, generation, and derived-cache cases.
+5. Run the request-reconstruction, compaction tool-pairing, compaction range, and workspace-context regression suites that consume the surface. In the implementation PR, update `packages/core/session/README.md`, `docs/core-data-structures/session.md`, the implemented session-surface RFC and its Chinese counterpart, the translation record, `scripts/type-equiv.manifest.json`, and the generated RFC index before moving this RFC pair to `implemented/`.
+
+## Alternatives considered
+
+**Keep acceptance and projection state separate.** Separate instances appear to isolate public reads from validation, but ordinary callers already receive borrowed surface state and cannot mutate it through the declared readonly contract. A cast that mutates the returned node array already corrupts derived history; duplicating the manager is not a sound runtime trust boundary.
+
+**Recompute the public surface from the full log on every access.** This removes cached duplicate state but gives up incremental derivation and makes repeated request construction scale with complete session history.
+
+## Acceptance criteria
+
+- A live `Session` owns exactly one incremental `SurfaceManager`.
+- Seed and append candidates are validated before publication with no partial surface mutation on rejection.
+- `session.surface`, derived messages, compaction, and workspace context observe the same nodes and replacement generation as the acceptance path.
+- `foldSurface()` remains available for detached replay and agrees with the live manager for every accepted prefix.
+- Session surface, seed, request reconstruction, compaction tool-pairing, and workspace-context tests pass.
+
+## Risks
+
+Sharing one manager makes the readonly borrowed-state contract more important because a hostile cast could corrupt both validation and projection state. The implementation should return a narrowed view and keep mutation methods inaccessible through `Session.surface`; JavaScript callers that deliberately bypass the type contract remain outside the supported same-process boundary.

docs/rfc/proposed/simplification/2026-07-19-use-one-session-surface-manager.zh.md

@@ -0,0 +1,43 @@
+# RFC: 每个会话只使用一个表层管理器
+
+Status: proposed
+
+[English](2026-07-19-use-one-session-surface-manager.md) | 中文
+
+## 问题
+
+`Session` 针对同一份仅追加事件日志维护两个 `SurfaceManager` 实例。`surfaceValidator` 主动校验种子事件与追加候选事件，延迟创建的 `_surface` 则独立折叠已提交事件，供 `session.surface`、派生消息、压缩（compaction）和工作区上下文使用。一旦读取公共表层，之后的每个事件都会推进两份重复的节点状态与替换代数状态。
+
+[会话表层决策](../../implemented/architecture/2026-06-18-session-surface.md)要求系统只保留一个有序表层，并使用一种表示完成校验。第二个管理器既不形成独立真源，也不保护不同的失败边界；它只会重复规范折叠，并使两个视图可能出现状态偏差。
+
+## 提案
+
+每个 `Session` 只保留一个 `SurfaceManager`。种子事件与追加事件的接纳流程仍在提交事件之前调用 `validateNext()`，公共表层视图则从同一个管理器读取 `nodes` 与 `replaceGeneration`。
+
+`Session.surface` 只公开只读表层契约，候选事件校验仍由 `Session` 负责。保留 `foldSurface()`，用于离线校验与重建时执行分离的完整日志回放。
+
+## 实施计划
+
+1. 在 `packages/core/session/src/surface.ts` 中，导出结构化的 `SessionSurface` 契约，只包含只读的 `nodes` 与 `replaceGeneration`，并让 `SurfaceManager` 实现该契约。从 `packages/core/session/src/index.ts` 重新导出这个类型，使 `Session.surface` 的声明不再暴露 `validateNext()`。
+2. 在 `Session` 中，用一个主动创建的 `surfaceManager` 替换 `surfaceValidator` 与延迟创建的 `_surface`。种子事件与追加事件都通过该管理器校验，`get surface(): SessionSurface` 返回同一个对象，`deriveMessages()` 也读取同一份节点与代数。`validateNext()` 可以同步已提交的日志事件，但对尚未提交的候选事件只能制定变更计划。候选事件在 `log.push()` 之后、下一次增量同步时才进入管理器状态，因此表层校验拒绝或提交前 `internal/dispatch` 否决都不会留下虚假状态。
+3. 保持 `foldSurface()` 与 `surface.ts` 中的状态转换函数不变。编译并验证 `packages/compact/compact/src/tool-pairing.ts`、`packages/compact/compact-basic/src/region.ts` 和 `packages/context/workspace-context/src/state.ts` 中的直接消费方；它们仍然只读取节点与替换代数。
+4. 扩展 `packages/core/session/tests/surface.spec.ts`：先读取公共视图，再提交无效候选事件，证明拒绝后节点与代数仍停留在已接纳前缀；随后追加有效事件，并把每个结果前缀与 `foldSurface()` 比较。在 `session.spec.ts` 中新增 `internal/dispatch` 否决用例与类型层面的 `SessionSurface` 断言，同时保留种子回放、增量增长、替换、代数和派生缓存用例。
+5. 运行消费表层的请求重建、压缩工具配对、压缩范围与工作区上下文回归套件。在实现 PR 中，先更新 `packages/core/session/README.md`、`docs/core-data-structures/session.md`、已实现会话表层 RFC 及其中文对应文件、翻译记录、`scripts/type-equiv.manifest.json` 和生成的 RFC 索引，再把本 RFC 双语文件移入 `implemented/`。
+
+## 备选方案
+
+**继续分离接纳状态与投影视图。** 两个独立实例看似能够隔离公共读取和校验，但普通调用方目前取得的就是借用的表层状态，无法通过声明的只读契约修改它。通过类型断言修改返回的节点数组，本就会破坏派生历史；复制管理器并不能构成可靠的运行时信任边界。
+
+**每次读取都根据完整日志重新计算公共表层。** 该方案不再缓存重复状态，但会放弃增量派生，使每次请求构造都随完整会话历史增长。
+
+## 验收标准
+
+- 每个活跃 `Session` 只拥有一个增量 `SurfaceManager`。
+- 种子事件与追加候选事件都在发布前完成校验，拒绝事件时不会留下只修改一半的表层状态。
+- `session.surface`、派生消息、压缩和工作区上下文观察到的节点与替换代数，和接纳路径使用的状态完全一致。
+- `foldSurface()` 仍可用于分离回放，并且对任意已接纳前缀都与活跃管理器一致。
+- 会话表层、种子、请求重建、压缩工具配对和工作区上下文测试全部通过。
+
+## 风险
+
+共享一个管理器会提高只读借用状态契约的重要性，因为恶意类型断言可能同时破坏校验状态和投影视图。实现应返回收窄后的视图，避免通过 `Session.surface` 暴露修改方法；刻意绕过类型契约的 JavaScript 调用方不属于受支持的同进程边界。

docs/rfc/rejected/simplification/2026-07-19-fold-compaction-package-split.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write
+2026-07-19-fold-compaction-package-split.md: 7c7a2da85beb956f8d6c24f813fc33aa350b5c0e
+2026-07-19-fold-compaction-package-split.zh.md: 37d75671d57226742608a525ea711b34780e65c6

docs/rfc/rejected/simplification/2026-07-19-fold-compaction-package-split.md

@@ -0,0 +1,37 @@
+# RFC: Fold the single compaction backend into its service package
+
+Status: rejected — More compaction backends are planned, so the interface and basic implementation packages remain separate.
+
+English | [中文](2026-07-19-fold-compaction-package-split.zh.md)
+
+## Problem
+
+Compaction is split between `@deepseek-ai/dsh-compact`, which owns an abstract two-method service and shared types, and `@deepseek-ai/dsh-compact-basic`, which owns the only complete implementation. Shipped configurations load only the basic package, and no production package independently consumes the interface package except that implementation.
+
+The split adds a package manifest, README, project boundary, dependency edge, abstract forwarding class, generated catalog entries, and composition wiring without demonstrating backend substitution. The [capability-seam decision](../../implemented/architecture/2026-06-13-capability-seams.md) requires a real interface, implementation, and consumer rather than a preemptive split; the [compaction decision](../../implemented/feature/2026-06-18-compaction-capability-seam.md) records that its independent consumer was deferred.
+
+## Proposal
+
+Move the basic implementation into `@deepseek-ai/dsh-compact` and remove `@deepseek-ai/dsh-compact-basic`. Keep `ctx.compact`, `CompactionResult`, the shared transcript and tool-pairing helpers, the existing configuration, and the concrete compaction algorithm in one package.
+
+Preserve `summarize()` as a protected customization hook. A deployment-specific summarizer can subclass or intercept the existing LLM call without requiring a second capability package. Reintroduce an interface package only when a second complete backend and an independent consumer need substitution.
+
+Amend the implemented compaction decision and the [recallable-compaction proposal](../../proposed/feature/2026-07-06-recallable-compaction.md) if this proposal is accepted so package ownership has one durable description.
+
+## Alternatives considered
+
+**Keep the split because a remote or recall backend may arrive.** A possible future implementation does not justify the current package boundary. Recall adds a consumer of compaction results, not necessarily another implementation, and a remote summarizer can use the protected hook.
+
+**Move the implementation package name onto the interface package.** Keeping `compact-basic` as the surviving name would make the product service appear to be one optional backend. `compact` is the stable service identity already used by `ctx.compact` and is the clearer single-package owner.
+
+## Acceptance criteria
+
+- `@deepseek-ai/dsh-compact-basic` and its workspace/package metadata are removed.
+- `@deepseek-ai/dsh-compact` owns the current configuration, plugin class, algorithm, types, events, and shared helpers.
+- Existing deployments can load the surviving package with equivalent configuration and model-visible behavior.
+- Automatic and manual compaction preserve cancellation, locking, token accounting, tool pairing, durable events, provenance, retry convergence, and transcript rendering.
+- Loader composition, unit, runaway-turn, cancellation, snapshot, and real-model compaction tests pass; generated catalogs and module graphs are current.
+
+## Risks
+
+This is an intentional pre-release package-name contraction. Embedders loading `@deepseek-ai/dsh-compact-basic` must switch packages, and future backend substitution would require extracting a boundary again. The cost is acceptable only while one complete implementation exists; acceptance should be revisited if a second backend lands first.

docs/rfc/rejected/simplification/2026-07-19-fold-compaction-package-split.zh.md

@@ -0,0 +1,37 @@
+# RFC: 将唯一的压缩后端并入服务包
+
+Status: rejected — 计划增加更多压缩后端，因此接口包与 basic 实现包继续分离。
+
+[English](2026-07-19-fold-compaction-package-split.md) | 中文
+
+## 问题
+
+压缩（compaction）目前拆分在两个包中：`@deepseek-ai/dsh-compact` 拥有一个含两个方法的抽象服务和共享类型，`@deepseek-ai/dsh-compact-basic` 拥有唯一的完整实现。交付配置只加载 basic 包，除了该实现外，没有生产包独立消费接口包。
+
+该拆分增加了一份包（package）manifest（元数据清单）、README、项目边界、依赖边、抽象转发类、生成目录项和组合接线，却没有体现后端替换需求。[能力服务边界决策](../../implemented/architecture/2026-06-13-capability-seams.md)要求接口、实现和消费方都必须真实存在，而不能预先拆分；[压缩决策](../../implemented/feature/2026-06-18-compaction-capability-seam.md)也记录了独立消费方仍被推迟。
+
+## 提案
+
+把 basic 实现移入 `@deepseek-ai/dsh-compact`，并删除 `@deepseek-ai/dsh-compact-basic`。`ctx.compact`、`CompactionResult`、共享 transcript（文本记录）和工具配对辅助方法、现有配置以及具体压缩算法都由一个包负责。
+
+保留 `summarize()` 作为受保护的自定义钩子。部署专用的摘要器可以通过继承或拦截现有 LLM（大语言模型）调用完成定制，无需第二个能力包。只有在第二个完整后端与独立消费方确实需要替换实现时，才重新提取接口包。
+
+如果本提案获准，应同步修订已实现的压缩决策与[可回忆压缩提案](../../proposed/feature/2026-07-06-recallable-compaction.md)，使包所有权只有一处持久说明。
+
+## 备选方案
+
+**为可能出现的远程或回忆后端保留拆分。** 一种可能的未来实现不足以支撑当前包边界。回忆功能会增加压缩结果的消费方，但不一定增加另一种实现；远程摘要器也可以使用受保护钩子。
+
+**让接口包并入实现包名。** 如果保留 `compact-basic` 作为最终名称，产品服务会看起来像一个可选后端。`compact` 已经是 `ctx.compact` 使用的稳定服务标识，更适合作为单包所有者。
+
+## 验收标准
+
+- 删除 `@deepseek-ai/dsh-compact-basic` 及其工作区和包元数据。
+- `@deepseek-ai/dsh-compact` 拥有当前配置、插件类、算法、类型、事件和共享辅助方法。
+- 现有部署可以使用等效配置加载保留的包，模型可见行为不变。
+- 自动压缩和手动压缩保留取消、锁、token 用量、工具配对、持久事件、来源、重试收敛和 transcript 渲染行为。
+- Loader 组合、单元、失控轮次、取消、快照和真实模型压缩测试全部通过；生成目录与模块图保持最新。
+
+## 风险
+
+这是一项有意实施的预发布包名收缩。加载 `@deepseek-ai/dsh-compact-basic` 的嵌入方必须切换包，未来的后端替换也需要重新提取边界。只有在仍然只有一个完整实现时，这项代价才可接受；如果第二个后端先行落地，应重新评估是否接纳本提案。