fix(subagent): require durability participant

.agents/notes/implemented/feature/2026-07-21-continuable-background-subagents.i18n.yaml

@@ -2,5 +2,5 @@
 # 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 .agents/notes/implemented/feature/2026-07-21-continuable-background-subagents.md
-2026-07-21-continuable-background-subagents.md: 42e9f6dd653dee8df4b8c068e3a33b7c69f8dc4b
-2026-07-21-continuable-background-subagents.zh.md: e643e81f40074c3cc0cd6398b3f1d24e0d9bc988
+2026-07-21-continuable-background-subagents.md: fc1cd97dae2583f6d78ee1413561002b6391a0c9
+2026-07-21-continuable-background-subagents.zh.md: 31775d9c2b8bd6b2dc84b5e86d4dbc9d1bd8a1f5

.agents/notes/implemented/feature/2026-07-21-continuable-background-subagents.md

@@ -31,7 +31,7 @@ The low-level `ctx.subagents` seam stays collection-, Task-, and persistence-agn
 
 ### Task and cancellation ownership
 
-The initial background delegation asks the control service to start the child and register its Task. A continuable provider confirms the activation's final session state durable before fulfilling a successful run result. Task settlement awaits that result, calls `run.dispose()` (through the control service's `settleRun`), and only then records the `TaskOutcome`; `task_kill` aborts the active run, whose settlement path still disposes it. A terminal Task therefore leaves the durable child session but no live child Agent. A failed required durability checkpoint rejects the run with stable code `DURABILITY_FAILED` and the backend failure as its cause; the control service records a failed Task whose detail explains that the latest state was not confirmed persisted and may be unavailable or stale on resume.
+The initial background delegation asks the control service to start the child and register its Task. A continuable provider confirms the activation's final session state durable before fulfilling a successful run result. Task settlement awaits that result, calls `run.dispose()` (through the control service's `settleRun`), and only then records the `TaskOutcome`; `task_kill` aborts the active run, whose settlement path still disposes it. A terminal Task therefore leaves the durable child session but no live child Agent. A required durability checkpoint with no installed listener or a failing listener rejects the run with stable code `DURABILITY_FAILED` and the checkpoint failure as its cause; the control service records a failed Task whose detail explains that the latest state was not confirmed persisted and may be unavailable or stale on resume.
 
 Every later turn creates another Task. Its producer resources cover only that activation, never the child session. It reaches one terminal status, has one result, and is never reopened. The exact live parent Agent remains the Task registry owner: disposing that instance cancels, awaits, and removes its Tasks. Task APIs authorize a caller whose session id matches that owner, but a same-id replacement does not become the notification or teardown target. This preserves the `settleRun()` contract and bounds Task-owned live children by concurrent work rather than historical session count.
 
@@ -109,7 +109,7 @@ Task records and active-run associations are process-local. Persistence makes th
 
 ## Testing
 
-- `packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts` pins the continuable durability boundary: a permanent flush failure rejects with `DURABILITY_FAILED` and its cause, a transient loop-checkpoint failure can succeed on the final confirmation, cancellation owns either final-checkpoint outcome, resume also confirms durability, and foreground runs remain best-effort. `packages/subagent/subagent/tests/continuation.spec.ts` drives the real stack (agent loop, JSONL persistence, spawn/fork providers, Task service, and `ctx.subagents`) keylessly: initial and resumed activations create fresh Tasks and dispose their runs before terminal; the descriptor event is turn-enclosed, model-hidden, versioned, and durable under the service-allocated child id; cancellation, steering, cold follow-up, authorization, ownership conflicts, and resume races retain the contracts described above.
+- `packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts` pins the continuable durability boundary: an absent or detached flush listener and a permanent listener failure reject with `DURABILITY_FAILED`, a transient loop-checkpoint failure can succeed on the final confirmation, cancellation owns either final-checkpoint outcome, resume also confirms durability, and foreground runs remain best-effort. `packages/subagent/subagent/tests/continuation.spec.ts` drives the real stack (agent loop, JSONL persistence, spawn/fork providers, Task service, and `ctx.subagents`) keylessly: initial and resumed activations create fresh Tasks and dispose their runs before terminal; the descriptor event is turn-enclosed, model-hidden, versioned, and durable under the service-allocated child id; cancellation, steering, cold follow-up, authorization, ownership conflicts, and resume races retain the contracts described above.
 - `packages/subagent/tool-subagent-control/tests/tool-subagent-control.spec.ts` pins the `send_message` schema, coordinator attribution, both route renderings, the not-delivered failure, the no-agent rejection, and HMR disposal.
 - `packages/subagent/tool-subagent/tests/tool-subagent.spec.ts` covers the configured background route: continuable mode requires a resumable provider and returns both ids without requiring `send_message`, while one-shot mode keeps the plain Task acknowledgement even when the provider can resume.
 - `packages/sdk/helper/tests/project.spec.ts` pins the Task service and model-facing Task controls in generated spawn and fork compositions.

.agents/notes/implemented/feature/2026-07-21-continuable-background-subagents.zh.md

@@ -31,7 +31,7 @@ durable child Session
 
 ### Task 与取消的所有权
 
-初始后台委派请求控制服务启动 child 并注册其 Task。可继续提供方只有在确认本次激活的最终会话状态已持久化后，才会返回成功的 run 结果。Task 结算流程等待该结果，调用 `run.dispose()`（经由控制服务的 `settleRun`），然后才记录 `TaskOutcome`；`task_kill` 中止活跃 run，其结算路径仍会 dispose 该 run。因此，终态 Task 会留下持久化 child 会话，但不会留下存活的 child agent。必需的持久性检查点失败时，run 会以稳定错误码 `DURABILITY_FAILED` 拒绝，并将后端失败保留为失败原因；控制服务会记录失败的 Task，其详情说明最新状态未确认已持久化，因此恢复时可能不可用或已陈旧。
+初始后台委派请求控制服务启动 child 并注册其 Task。可继续提供方只有在确认本次激活的最终会话状态已持久化后，才会返回成功的 run 结果。Task 结算流程等待该结果，调用 `run.dispose()`（经由控制服务的 `settleRun`），然后才记录 `TaskOutcome`；`task_kill` 中止活跃 run，其结算路径仍会 dispose 该 run。因此，终态 Task 会留下持久化 child 会话，但不会留下存活的 child agent。必需的持久性检查点若没有已安装的监听器或任一监听器失败，run 会以稳定错误码 `DURABILITY_FAILED` 拒绝，并将检查点失败保留为失败原因；控制服务会记录失败的 Task，其详情说明最新状态未确认已持久化，因此恢复时可能不可用或已陈旧。
 
 后续每个轮次都会创建另一个 Task。该轮 producer 持有的执行资源仅服务于这次激活，不属于 child 会话。它只会到达一次终态、只产生一个结果，也不会重新打开。Task 注册表中当前注册的那个存活 parent agent 实例仍是其 owner：dispose 该实例会取消、等待并移除其 Task。Task API 会授权 session id 与该 owner 匹配的调用方，但 id 相同的替代实例不会成为通知或资源清理目标。这一设计保留 `settleRun()` 契约，并使 Task 所拥有的存活 child 数量受并发工作量限制，而不是随历史会话数量增长。
 
@@ -109,7 +109,7 @@ Task 记录和活跃 run 关联都位于进程内。持久化使 child 会话可
 
 ## 测试
 
-- `packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts` 固定可继续执行的持久性边界：flush 持续失败时会以 `DURABILITY_FAILED` 拒绝并保留失败原因，循环检查点的瞬时失败可在最终确认成功后继续完成，发生取消时最终检查点无论成功还是失败都由取消优先决定结果，resume 同样会确认持久性，而前台运行仍采用尽力而为策略。`packages/subagent/subagent/tests/continuation.spec.ts` 以无密钥方式驱动真实栈（agent loop、JSONL 持久化、spawn／fork 提供方、Task 服务和 `ctx.subagents`）：初始及恢复后的激活都会创建新 Task，并在进入终态前 dispose 各自的 run；描述符事件位于轮次内、对模型隐藏、带版本，并在服务分配的 child id 下持久化；取消、steering、cold follow-up、授权、所有权冲突与 resume 竞态保留上述契约。
+- `packages/subagent/subagent-inprocess/tests/subagent-inprocess.spec.ts` 固定可继续执行的持久性边界：缺少 flush 监听器、flush 监听器已脱离或监听器持续失败时，均会以 `DURABILITY_FAILED` 拒绝；循环检查点的瞬时失败可在最终确认成功后继续完成，发生取消时最终检查点无论成功还是失败都由取消优先决定结果，resume 同样会确认持久性，而前台运行仍采用尽力而为策略。`packages/subagent/subagent/tests/continuation.spec.ts` 以无密钥方式驱动真实栈（agent loop、JSONL 持久化、spawn／fork 提供方、Task 服务和 `ctx.subagents`）：初始及恢复后的激活都会创建新 Task，并在进入终态前 dispose 各自的 run；描述符事件位于轮次内、对模型隐藏、带版本，并在服务分配的 child id 下持久化；取消、steering、cold follow-up、授权、所有权冲突与 resume 竞态保留上述契约。
 - `packages/subagent/tool-subagent-control/tests/tool-subagent-control.spec.ts` 固定 `send_message` 的 schema、coordinator 来源标记、两种路由渲染、未送达失败、无 agent 时的拒绝，以及 HMR（热模块替换）dispose。
 - `packages/subagent/tool-subagent/tests/tool-subagent.spec.ts` 覆盖配置的后台路由：可继续模式要求提供方可恢复，并在不要求 `send_message` 的情况下返回两个 id；即使提供方可以恢复，一次性模式仍保持普通的 Task 确认消息。
 - `packages/sdk/helper/tests/project.spec.ts` 固定生成的 spawn 与 fork 组合中的 Task 服务及面向模型的 Task 控制工具。