diff --git a/.agents/notes/implemented/feature/2026-08-26-human-job-kill.i18n.yaml b/.agents/notes/implemented/feature/2026-08-26-human-job-kill.i18n.yaml
index 7705e75ac0..df6cf0e7c2 100644
--- a/.agents/notes/implemented/feature/2026-08-26-human-job-kill.i18n.yaml
+++ b/.agents/notes/implemented/feature/2026-08-26-human-job-kill.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/2026-08-26-human-job-kill.md
-2026-08-26-human-job-kill.md: 9ef2d66e129ea70fa927528717f87e4cfec66a1b
-2026-08-26-human-job-kill.zh.md: 1b9933b5af48b736fce4a6562338ff9f1d75c6d4
+2026-08-26-human-job-kill.md: 2242ed2cf5612394f6797106decf75d8543fc420
+2026-08-26-human-job-kill.zh.md: 37a2d2b38bfa74aaaef6c5ba34fa8e0c7761178b
diff --git a/.agents/notes/implemented/feature/2026-08-26-human-job-kill.md b/.agents/notes/implemented/feature/2026-08-26-human-job-kill.md
index 9ef2d66e12..2242ed2cf5 100644
--- a/.agents/notes/implemented/feature/2026-08-26-human-job-kill.md
+++ b/.agents/notes/implemented/feature/2026-08-26-human-job-kill.md
@@ -14,8 +14,8 @@ The `reported` bit means "the terminal state has a committed delivery path to th
 
 - **`kill(id, caller?, options?)` takes `{ reason?, reported? }`.** `reported` defaults to `true` — the exact previous semantics for the model's `job_kill`. `reported: false` withholds this kill's claim, so the settlement flows through the existing completion reporter (wakeup/inject, wake budget, truncation all unchanged). It never clears an existing claim: a job the model already killed stays reported, and a terminal record stays exactly as settlement left it.
 - **A recorded kill reason merges into a `killed` settlement's detail** — producer facts first (`signal: SIGTERM; cancelled by the user`) — so the completion notice and the web row both say who stopped the work without a new snapshot field or notice template. A job that outruns its kill (settles `completed`/`failed`) keeps the producer detail alone. This is the reconciliation Codex spells out in its `<turn_aborted>` guidance: when the user stops something, the model is told rather than left to infer.
-- **`session.killJob` is a Session Controller Remote** beside `cancel`, with the same live-only Agent lookup (`ctx.agents.get`): a running job's owner is alive by the registry's ownership contract, and killing from a list must not revive a Session any more than listing does. Unknown and foreign jobs collapse to one `job-not-found` rejection; a composition without `ctx.jobs` rejects `jobs-unavailable`. No approval interaction: this single-user local BFF treats it as the same class of action as the turn-cancel button.
-- **The task list's stop control is two-press** (arm, then confirm within 3s, matching the Kimi `s`+`y` and OpenCode double-Esc shape), rendered only on running job rows — rows with a `jobId`. Standalone activity rows (workflow runs) have no kill handle and no button. The pending press disables the control; the row's own `stopping` flip from the jobs frames removes it, and a rejected kill shows a brief hint. Because the kill addresses `ctx.jobs` by id, every job kind gains the control at once — bash, pwsh, pty, and one-shot background subagents.
+- **`session.killJob` is a Session Controller Remote** beside `cancel`, with the same live-only Agent lookup (`ctx.agents.get`): a running job's owner is alive by the registry's ownership contract, and killing from a list must not revive a Session any more than listing does. Unknown and foreign jobs collapse to one `job-not-found` rejection scoped to the lookup — a producer-cancel throw propagates per the registry contract instead of masquerading as a lookup failure; a composition without `ctx.jobs` rejects `jobs-unavailable`, and the service-wide subagent ownership fence applies exactly as it does to `cancel`. No approval interaction: this single-user local BFF treats it as the same class of action as the turn-cancel button.
+- **The task list's stop control is two-press** (arm, then confirm within 3s, matching the Kimi `s`+`y` and OpenCode double-Esc shape), rendered only on running job rows — rows with a `jobId`. Standalone activity rows (workflow runs) have no kill handle and no button. The pending press disables the control and stays pending on an admitted kill — the unary response and the jobs frames have no cross-carrier ordering, so only the authoritative frame (the row leaving the killable set) releases it; a rejected kill shows a brief hint. Because the kill addresses `ctx.jobs` by id, every job kind gains the control at once — bash, pwsh, pty, and one-shot background subagents.
 
 ## Alternatives considered
 
diff --git a/.agents/notes/implemented/feature/2026-08-26-human-job-kill.zh.md b/.agents/notes/implemented/feature/2026-08-26-human-job-kill.zh.md
index 1b9933b5af..37a2d2b38b 100644
--- a/.agents/notes/implemented/feature/2026-08-26-human-job-kill.zh.md
+++ b/.agents/notes/implemented/feature/2026-08-26-human-job-kill.zh.md
@@ -14,8 +14,8 @@
 
 - **`kill(id, caller?, options?)` 接受 `{ reason?, reported? }`。** `reported` 默认 `true`——即模型 `job_kill` 的原有语义。`reported: false` 只是不提出本次 kill 的认领，结算随即照常走完成播报员（唤醒/注入、唤醒预算、截断全部不变）。它绝不清除已有认领：模型已 kill 过的任务保持 reported，终态记录也保持结算时的原样。
 - **记录下来的 kill reason 合入 `killed` 结算的 detail**——生产者事实在前（`signal: SIGTERM; cancelled by the user`）——完成通知与 Web 行因此都能说清是谁停的工作，无需新快照字段或新通知模板。跑赢 kill 的任务（结算为 `completed`/`failed`）只保留生产者 detail。这正是 Codex 在 `<turn_aborted>` 指引里写明的对账原则：用户停掉了什么，要告诉模型，而不是让它去猜。
-- **`session.killJob` 是 Session Controller 的 Remote**，与 `cancel` 并列，同样只查活体 Agent（`ctx.agents.get`）：按注册表的所有权契约，在跑任务的 owner 必然活着；从列表里 kill 与列表本身一样绝不复活 Session。未知与他人任务合并为一个 `job-not-found` 拒绝；没有 `ctx.jobs` 的组合拒绝 `jobs-unavailable`。不加 approval 交互：这个单用户本地 BFF 把它视为与停轮按钮同级的操作。
-- **任务列表的停止控件为两击式**（先武装、3 秒内确认，对齐 Kimi 的 `s`+`y` 与 OpenCode 的双 Esc），只渲染在运行中的 job 行——即带 `jobId` 的行。独立 activity 行（workflow 运行）没有 kill 句柄也就没有按钮。请求进行中按钮禁用；jobs 帧把行翻成 `stopping` 即移除按钮，被拒绝的 kill 短暂提示。由于 kill 按 id 寻址 `ctx.jobs`，所有任务 kind 一次性获得该控件——bash、pwsh、pty 与一次性后台 subagent。
+- **`session.killJob` 是 Session Controller 的 Remote**，与 `cancel` 并列，同样只查活体 Agent（`ctx.agents.get`）：按注册表的所有权契约，在跑任务的 owner 必然活着；从列表里 kill 与列表本身一样绝不复活 Session。未知与他人任务合并为一个只作用于查找的 `job-not-found` 拒绝——生产者 cancel 抛错按注册表契约原样传播，绝不伪装成查找失败；没有 `ctx.jobs` 的组合拒绝 `jobs-unavailable`，服务级的 subagent 所有权栅栏与 `cancel` 完全一致地适用。不加 approval 交互：这个单用户本地 BFF 把它视为与停轮按钮同级的操作。
+- **任务列表的停止控件为两击式**（先武装、3 秒内确认，对齐 Kimi 的 `s`+`y` 与 OpenCode 的双 Esc），只渲染在运行中的 job 行——即带 `jobId` 的行。独立 activity 行（workflow 运行）没有 kill 句柄也就没有按钮。请求进行中按钮禁用，且受理成功后保持 pending——unary 响应与 jobs 帧没有跨载体顺序保证，只有权威帧（行离开可杀集合）才释放控件；被拒绝的 kill 短暂提示。由于 kill 按 id 寻址 `ctx.jobs`，所有任务 kind 一次性获得该控件——bash、pwsh、pty 与一次性后台 subagent。
 
 ## 备选方案
 
diff --git a/packages/api/session-controller/src/commands.ts b/packages/api/session-controller/src/commands.ts
index 845a34fb44..1a0eb183c1 100644
--- a/packages/api/session-controller/src/commands.ts
+++ b/packages/api/session-controller/src/commands.ts
@@ -451,7 +451,8 @@ export class SessionCommandController {
    * the standard completion notice — a human cancellation has no other
    * model-visible channel. The Agent lookup is live-only: a running job's
    * owner is alive by the registry's ownership contract, and listing never
-   * revives a Session, so neither does killing from its list.
+   * revives a Session, so neither does killing from its list. The service-wide
+   * subagent ownership fence applies exactly as it does to `cancel`.
    * @param request - Session whose task list carries the job, and the job id.
    * @returns the registry's admission of the kill request.
    */
@@ -461,12 +462,11 @@ export class SessionCommandController {
       reject('jobs-unavailable', 'background jobs are not available in this composition', {})
     }
     const agent = this.ctx.agents.get(request.sessionId)
+    if (agent !== undefined && hasApiSessionSubagentOwner(this.ctx, agent.session, agent)) {
+      rejectFailure(apiSessionSubagentOwnershipError(request.sessionId))
+    }
     try {
-      const outcome = jobs.kill(request.jobId, agent, {
-        reason: 'cancelled by the user',
-        reported: false,
-      })
-      return { outcome }
+      jobs.get(request.jobId, agent)
     } catch (error) {
       // `unknown job` and `belongs to another session` both mean this session's
       // list no longer carries a killable row; the client renders one story.
@@ -475,6 +475,14 @@ export class SessionCommandController {
         jobId: request.jobId,
       })
     }
+    // Same synchronous span as the lookup, so nothing can remove the job in
+    // between — and a producer-cancel throw now propagates per the registry
+    // contract (job state unchanged) instead of masquerading as job-not-found.
+    const outcome = jobs.kill(request.jobId, agent, {
+      reason: 'cancelled by the user',
+      reported: false,
+    })
+    return { outcome }
   }
 
   private async resolveAgent(sessionId: SessionId): Promise<Agent> {
diff --git a/packages/api/session-controller/tests/kill-job.host.spec.ts b/packages/api/session-controller/tests/kill-job.host.spec.ts
index 0cb4c41d01..5173739b25 100644
--- a/packages/api/session-controller/tests/kill-job.host.spec.ts
+++ b/packages/api/session-controller/tests/kill-job.host.spec.ts
@@ -117,4 +117,40 @@ describe('session.killJob', () => {
     expect(failureCode(() => commands.killJob({ sessionId: session.id, jobId: 'bash-1' as JobId })))
       .toBe('jobs-unavailable')
   })
+
+  it('propagates a producer cancel throw instead of masking it as job-not-found', async () => {
+    const { ctx, session, agent, commands } = await harness()
+    const id = ctx.jobs.start({
+      kind: 'bash',
+      label: 'flaky cancel',
+      owner: agent,
+      run: () => ({
+        cancel: () => { throw new Error('cancel boom') },
+        done: new Promise(() => {}),
+      }),
+    })
+    // The registry contract: a producer throw propagates with job state
+    // unchanged — the command must not rewrite it into a lookup failure.
+    expect(() => commands.killJob({ sessionId: session.id, jobId: id })).toThrow('cancel boom')
+    expect(ctx.jobs.get(id, agent)).toMatchObject({ status: 'running', reported: false })
+  })
+
+  it('rejects a subagent-owned live session with the ownership fence', async () => {
+    const { ctx, commands } = await harness()
+    const child = ctx.sessions.create(undefined, { meta: { origin: 'subagent' } })
+    const childAgent = {
+      id: child.id,
+      session: child,
+      inbox: new Inbox(child, { inserted: () => {}, discarded: () => {}, claimed: () => {} }),
+      status: 'idle',
+      ctx,
+    } as Agent
+    ctx.agents.register(childAgent)
+    const task = producer('child work')
+    const id = ctx.jobs.start({ ...task.spec, owner: childAgent })
+
+    expect(failureCode(() => commands.killJob({ sessionId: child.id, jobId: id })))
+      .toBe('agent-busy')
+    expect(ctx.jobs.get(id, childAgent).status).toBe('running')
+  })
 })
diff --git a/packages/client/ui-activity/src/client/ActivityListAction.tsx b/packages/client/ui-activity/src/client/ActivityListAction.tsx
index ea7914d849..44e1887c52 100644
--- a/packages/client/ui-activity/src/client/ActivityListAction.tsx
+++ b/packages/client/ui-activity/src/client/ActivityListAction.tsx
@@ -485,10 +485,13 @@ export function ActivityListAction({ sessionId, useSessions, useActivity, observ
     }
     setKillPhase({ key: row.key, state: 'pending' })
     void killJob(sessionId, jobId).then((ok) => {
-      // Success needs no local state: the jobs frame flips the row to
-      // `stopping`, which removes the button and clears the phase above.
-      setKillPhase(current => current?.key === row.key
-        ? (ok ? undefined : { key: row.key, state: 'failed' })
+      // An admitted kill stays pending: the unary response (HTTP) and the jobs
+      // frames (control stream) have no cross-carrier ordering, so re-enabling
+      // here could offer a duplicate kill while the row still reads `running`.
+      // The authoritative jobs frame flips the row to `stopping`, which removes
+      // the button and clears the phase through the killable-set effect above.
+      setKillPhase(current => current?.key === row.key && !ok
+        ? { key: row.key, state: 'failed' }
         : current)
     })
   }
diff --git a/packages/client/ui-activity/tests/activity-list-action.client.spec.tsx b/packages/client/ui-activity/tests/activity-list-action.client.spec.tsx
index 28276e5fcb..ae4c8745fe 100644
--- a/packages/client/ui-activity/tests/activity-list-action.client.spec.tsx
+++ b/packages/client/ui-activity/tests/activity-list-action.client.spec.tsx
@@ -407,9 +407,11 @@ describe('ActivityListAction human kill', () => {
     expect(screen.getByTitle(zh['kill.confirm'])).toBe(stop)
     await act(async () => { fireEvent.click(stop) })
     expect(killJob).toHaveBeenCalledWith(SESSION, 'bash-1')
-    // The accepted kill leaves row convergence to the jobs frames; the local
-    // phase resets so the control does not stick in pending.
-    expect(stop.getAttribute('data-kill-state')).toBe('idle')
+    // An admitted kill stays pending: the unary response and the jobs frames
+    // have no cross-carrier ordering, so only the authoritative frame (the row
+    // leaving the killable set) releases the control — never the response.
+    expect(stop.getAttribute('data-kill-state')).toBe('pending')
+    expect(stop.hasAttribute('disabled')).toBe(true)
   })
 
   it('an armed press disarms after the confirmation window', () => {
diff --git a/packages/jobs/jobs-local/src/index.ts b/packages/jobs/jobs-local/src/index.ts
index 2db513b520..51b365ca0d 100644
--- a/packages/jobs/jobs-local/src/index.ts
+++ b/packages/jobs/jobs-local/src/index.ts
@@ -228,6 +228,8 @@ export class LocalJobRegistry extends JobRegistry {
     // Cancel first so a throw leaves both lifecycle and notice state unchanged.
     job.cancel(options?.reason)
     job.status = 'stopping'
+    // Last writer wins on purpose: the detail reports the latest kill intent,
+    // while `reported` above keeps first-claim-wins for notice delivery.
     if (options?.reason !== undefined) job.killReason = options.reason
     if (claims) job.reported = true
     this.notifyChanged(job.owner)