diff --git a/docs/config-catalog.md b/docs/config-catalog.md
index a0cbac6789..f07dfcf18a 100644
--- a/docs/config-catalog.md
+++ b/docs/config-catalog.md
@@ -918,7 +918,7 @@ export interface Config {
 
 Depends on: [`SubagentCapabilities`](../packages/subagent/subagent/src/index.ts) · [`SubagentStopReason`](../packages/subagent/subagent/src/index.ts)
 
-Source: [`packages/support/subagent-mock/src/index.ts:86`](../packages/support/subagent-mock/src/index.ts)
+Source: [`packages/support/subagent-mock/src/index.ts:87`](../packages/support/subagent-mock/src/index.ts)
 
 ## `@deepseek-ai/dsh-subagent-spawn`
 
diff --git a/docs/cordis-catalog/events.md b/docs/cordis-catalog/events.md
index 820a453ceb..d0ff7002b0 100644
--- a/docs/cordis-catalog/events.md
+++ b/docs/cordis-catalog/events.md
@@ -301,7 +301,7 @@ A ready child settled. Scope-filtered dispatch uses the same delegating parent c
 'subagent/end'(this: Scoped<SubagentService>, info: SubagentRunEndInfo): void
 ```
 
-Source: [`packages/subagent/subagent/src/index.ts:109`](../../packages/subagent/subagent/src/index.ts)
+Source: [`packages/subagent/subagent/src/index.ts:112`](../../packages/subagent/subagent/src/index.ts)
 
 ### `subagent/provider-added` — emit
 
@@ -311,7 +311,7 @@ A provider became resolvable in the registry.
 'subagent/provider-added'(provider: SubagentProvider): void
 ```
 
-Source: [`packages/subagent/subagent/src/index.ts:83`](../../packages/subagent/subagent/src/index.ts)
+Source: [`packages/subagent/subagent/src/index.ts:86`](../../packages/subagent/subagent/src/index.ts)
 
 ### `subagent/provider-removed` — emit
 
@@ -321,7 +321,7 @@ A provider left the registry. Accepted runs remain holder-owned.
 'subagent/provider-removed'(name: string): void
 ```
 
-Source: [`packages/subagent/subagent/src/index.ts:89`](../../packages/subagent/subagent/src/index.ts)
+Source: [`packages/subagent/subagent/src/index.ts:92`](../../packages/subagent/subagent/src/index.ts)
 
 ### `subagent/start` — emit
 
@@ -331,7 +331,7 @@ A provider established a ready child. For in-process providers, `ctx.agents.get(
 'subagent/start'(this: Scoped<SubagentService>, info: SubagentRunInfo): void
 ```
 
-Source: [`packages/subagent/subagent/src/index.ts:100`](../../packages/subagent/subagent/src/index.ts)
+Source: [`packages/subagent/subagent/src/index.ts:103`](../../packages/subagent/subagent/src/index.ts)
 
 ## `system-prompt/*`
 
diff --git a/docs/cordis-catalog/services.md b/docs/cordis-catalog/services.md
index 52f9cdf131..ee953e37c7 100644
--- a/docs/cordis-catalog/services.md
+++ b/docs/cordis-catalog/services.md
@@ -264,7 +264,7 @@ list(): string[]
 async start(name: string, request: SubagentStartRequest): Promise<SubagentRun>
 ```
 
-Source: [`packages/subagent/subagent/src/index.ts:142`](../../packages/subagent/subagent/src/index.ts)
+Source: [`packages/subagent/subagent/src/index.ts:153`](../../packages/subagent/subagent/src/index.ts)
 
 ## `ctx.systemPrompt` — `SystemPrompt`
 
diff --git a/docs/core-data-structures/subagent.md b/docs/core-data-structures/subagent.md
index 18cb22c32d..815438f215 100644
--- a/docs/core-data-structures/subagent.md
+++ b/docs/core-data-structures/subagent.md
@@ -69,6 +69,7 @@ interface SubagentStopReasonMap {
 ```ts type-equiv
 interface SubagentRun {
   readonly id: SessionId
+  readonly localAgent: Agent | undefined
   readonly result: Promise<SubagentResult>
   dispose(): Promise<void>
   sendMessage?(content: ContentBlock[]): void
@@ -76,7 +77,7 @@ interface SubagentRun {
 }
 ```
 
-A local run MUST publish an ordinary child agent/session before `start()` fulfills, return that child session id as `SubagentRun.id`, and record `request.parent.session.id` in the child's `parentSession` header. Runtime ownership may place the child under the parent, provider, or root scope; `parentSession` is the durable transport-neutral lineage. A remote provider instead returns a parent-scoped lifecycle id and does not publish a local child.
+A local run MUST publish an ordinary child agent/session before `start()` fulfills, return that child session id as `SubagentRun.id`, expose the exact child as `localAgent`, and record `request.parent.session.id` in the child's `parentSession` header. Runtime ownership may place the child under the parent, provider, or root scope. A remote provider instead returns a parent-scoped lifecycle id and `localAgent: undefined`.
 
 ## The provider seam: `SubagentProvider`
 
@@ -91,7 +92,7 @@ interface SubagentProvider {
 }
 ```
 
-`start()` fulfills only with a ready run. The service observes its result, emits `subagent/start`, and returns the same run; rejection implies provider cleanup and emits no lifecycle pair. In-process children are discoverable through `ctx.agents`, while remote children need not be. `subagent/end` reports final output or infrastructure failure. Both events are observe-only and contain listener exceptions.
+`start()` fulfills only with a ready run. The service mints a unique `runId`, snapshots `local` from the provider's exact `localAgent`, observes the result, emits `subagent/start`, and returns the same run; rejection implies provider cleanup and emits no lifecycle pair. The paired `subagent/end` carries the same identity and the final output or infrastructure failure. Both events are observe-only and contain listener exceptions.
 
 ## In-process backends: depth and seed
 
diff --git a/docs/event-producer-consumer.md b/docs/event-producer-consumer.md
index 6d75d54f3d..49e8d778cf 100644
--- a/docs/event-producer-consumer.md
+++ b/docs/event-producer-consumer.md
@@ -30,10 +30,10 @@ This matrix shows which packages dispatch each harness-owned event and which pac
 | `session/disposed` | `emit` | [`packages/core/session/src/index.ts:56`](../packages/core/session/src/index.ts) | [`session`](../packages/core/session) (`events.dispatch`) | [`agent-loop`](../packages/core/agent-loop), [`session-persistence`](../packages/session-persistence/session-persistence) |
 | `session/event` | `emit` | [`packages/core/session/src/index.ts:68`](../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`](../packages/ui/stdio), [`token-meter`](../packages/llm/token-meter), [`workspace-context`](../packages/context/workspace-context) |
 | `session/flush` | `parallel` | [`packages/core/session/src/index.ts:78`](../packages/core/session/src/index.ts) | [`session`](../packages/core/session) (`events.dispatch`) | [`session-persistence`](../packages/session-persistence/session-persistence) |
-| `subagent/end` | `emit` | [`packages/subagent/subagent/src/index.ts:109`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`events.dispatch`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`jsonrpc`](../packages/ui/jsonrpc) |
-| `subagent/provider-added` | `emit` | [`packages/subagent/subagent/src/index.ts:83`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`emit`) | [`tool-subagent`](../packages/subagent/tool-subagent) |
-| `subagent/provider-removed` | `emit` | [`packages/subagent/subagent/src/index.ts:89`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`events.dispatch`) | [`tool-subagent`](../packages/subagent/tool-subagent) |
-| `subagent/start` | `emit` | [`packages/subagent/subagent/src/index.ts:100`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`events.dispatch`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`jsonrpc`](../packages/ui/jsonrpc) |
+| `subagent/end` | `emit` | [`packages/subagent/subagent/src/index.ts:112`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`events.dispatch`) | [`hooks-claude`](../packages/hooks/hooks-claude), [`jsonrpc`](../packages/ui/jsonrpc) |
+| `subagent/provider-added` | `emit` | [`packages/subagent/subagent/src/index.ts:86`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`emit`) | [`tool-subagent`](../packages/subagent/tool-subagent) |
+| `subagent/provider-removed` | `emit` | [`packages/subagent/subagent/src/index.ts:92`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`events.dispatch`) | [`tool-subagent`](../packages/subagent/tool-subagent) |
+| `subagent/start` | `emit` | [`packages/subagent/subagent/src/index.ts:103`](../packages/subagent/subagent/src/index.ts) | [`subagent`](../packages/subagent/subagent) (`events.dispatch`) | [`hooks-claude`](../packages/hooks/hooks-claude) |
 | `system-prompt/assemble` | `waterfall` | [`packages/core/system-prompt/src/index.ts:27`](../packages/core/system-prompt/src/index.ts) | [`system-prompt`](../packages/core/system-prompt) (`waterfall`) | [`acp`](../packages/ui/acp) |
 | `system-prompt/change` | `emit` | [`packages/core/system-prompt/src/index.ts:33`](../packages/core/system-prompt/src/index.ts) | [`system-prompt`](../packages/core/system-prompt) (`emit`) | - |
 | `tools/change` | `emit` | [`packages/core/tools/src/index.ts:116`](../packages/core/tools/src/index.ts) | [`tools`](../packages/core/tools) (`emit`) | - |
diff --git a/docs/module-graph.md b/docs/module-graph.md
index 604aa7cf7f..f49092f99d 100644
--- a/docs/module-graph.md
+++ b/docs/module-graph.md
@@ -279,6 +279,7 @@ flowchart TD
   pkg_tool_skill --> pkg_skill
   pkg_tool_skill --> pkg_tools
   pkg_subagent --> pkg_agent
+  pkg_subagent --> pkg_brand
   pkg_subagent --> pkg_llm
   pkg_subagent --> pkg_scope
   pkg_subagent --> pkg_session
@@ -493,7 +494,7 @@ flowchart TD
 | [`tool-fs`](../packages/fs/tool-fs) | `fs` | [`fs`](../packages/fs/fs), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools) |
 | [`tool-fs-search`](../packages/fs/tool-fs-search) | `fs` | [`bash`](../packages/bash/bash), [`llm`](../packages/llm/llm), [`retention`](../packages/util/retention), [`session`](../packages/core/session), [`spill`](../packages/spill/spill), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools) |
 | [`tool-skill`](../packages/skill/tool-skill) | `skill` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`skill`](../packages/skill/skill), [`tools`](../packages/core/tools) |
-| [`subagent`](../packages/subagent/subagent) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`scope`](../packages/core/scope), [`session`](../packages/core/session), [`tools`](../packages/core/tools) |
+| [`subagent`](../packages/subagent/subagent) | `subagent` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`llm`](../packages/llm/llm), [`scope`](../packages/core/scope), [`session`](../packages/core/session), [`tools`](../packages/core/tools) |
 | [`tool-web`](../packages/web/tool-web) | `web` | [`llm`](../packages/llm/llm), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools), [`web`](../packages/web/web) |
 | [`spill-policy`](../packages/spill/spill-policy) | `spill` | [`llm`](../packages/llm/llm), [`retention`](../packages/util/retention), [`session`](../packages/core/session), [`spill`](../packages/spill/spill), [`tools`](../packages/core/tools) |
 | [`timeout-policy`](../packages/timeout/timeout-policy) | `timeout` | [`llm`](../packages/llm/llm), [`timeout`](../packages/util/timeout), [`tools`](../packages/core/tools) |
diff --git a/packages/cordis/tool-cordis/src/api-catalog.ts b/packages/cordis/tool-cordis/src/api-catalog.ts
index 71640498c9..ed5c0babe9 100644
--- a/packages/cordis/tool-cordis/src/api-catalog.ts
+++ b/packages/cordis/tool-cordis/src/api-catalog.ts
@@ -1028,7 +1028,7 @@ export const TYPE_API: readonly TypeApiEntry[] = [
   },
   {
     name: 'SubagentRun',
-    declaration: 'export interface SubagentRun {\n    readonly id: SessionId;\n    readonly result: Promise<SubagentResult>;\n    dispose(): Promise<void>;\n    sendMessage?(content: ContentBlock[]): void;\n    resume?(content: ContentBlock[]): Promise<SubagentRun>;\n}',
+    declaration: 'export interface SubagentRun {\n    readonly id: SessionId;\n    readonly localAgent: Agent | undefined;\n    readonly result: Promise<SubagentResult>;\n    dispose(): Promise<void>;\n    sendMessage?(content: ContentBlock[]): void;\n    resume?(content: ContentBlock[]): Promise<SubagentRun>;\n}',
   },
   {
     name: 'SubagentStartRequest',
diff --git a/packages/hooks/hooks-claude/tests/bridge.spec.ts b/packages/hooks/hooks-claude/tests/bridge.spec.ts
index 136ee893c6..7bb4c0b4ea 100644
--- a/packages/hooks/hooks-claude/tests/bridge.spec.ts
+++ b/packages/hooks/hooks-claude/tests/bridge.spec.ts
@@ -9,6 +9,7 @@ import { defineTool } from '@deepseek-ai/dsh-tools'
 import AgentLoop, { type ReactLoopAgent } from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
 import { LocalBashExecutor } from '@deepseek-ai/dsh-bash-local'
+import { SubagentRunId } from '@deepseek-ai/dsh-subagent'
 import * as HooksClaude from '@deepseek-ai/dsh-hooks-claude'
 import { MockAdapter, textResponse, toolCallResponse } from '../../../core/agent-loop/tests/mock-adapter.ts'
 
@@ -288,8 +289,8 @@ describe('hooks-claude bridge — SubagentStart / SubagentStop (observe)', () =>
     // Drive the observe-only lifecycle events directly (no real child needed — the
     // bridge just listens). No child agent is registered, so SubagentStart's
     // child lookup yields undefined and it simply runs the hook.
-    ctx.emit('subagent/start', { provider: 'inproc', id: SessionId('child-1') })
-    ctx.emit('subagent/end', { provider: 'inproc', id: SessionId('child-1'), stopReason: 'completed', lastAssistantMessage: [{ type: 'text', text: 'done' }] })
+    ctx.emit('subagent/start', { runId: SubagentRunId('run-1'), provider: 'inproc', id: SessionId('child-1'), local: false })
+    ctx.emit('subagent/end', { runId: SubagentRunId('run-1'), provider: 'inproc', id: SessionId('child-1'), local: false, stopReason: 'completed', lastAssistantMessage: [{ type: 'text', text: 'done' }] })
 
     // Both hooks run async (detached .then); poll for their marker files rather
     // than a fixed sleep that flakes under load.
@@ -324,7 +325,7 @@ describe('hooks-claude bridge — SubagentStart / SubagentStop (observe)', () =>
     const { ctx, hooks } = await harnessWithFiber(dir, new MockAdapter([]))
     const warn = vi.fn()
     ctx.logger.warn = warn as never
-    ctx.emit('subagent/start', { provider: 'inproc', id: SessionId('child-1') })
+    ctx.emit('subagent/start', { runId: SubagentRunId('run-1'), provider: 'inproc', id: SessionId('child-1'), local: false })
     await waitFor(() => existsSync(marker))
     const pid = Number(readFileSync(pidFile, 'utf8').trim())
     await hooks.dispose()
diff --git a/packages/hooks/hooks-claude/tests/coverage-cases.ts b/packages/hooks/hooks-claude/tests/coverage-cases.ts
index 9d4004c1ff..0431486d57 100644
--- a/packages/hooks/hooks-claude/tests/coverage-cases.ts
+++ b/packages/hooks/hooks-claude/tests/coverage-cases.ts
@@ -9,6 +9,7 @@ import { defineTool } from '@deepseek-ai/dsh-tools'
 import AgentLoop, { type ReactLoopAgent } from '@deepseek-ai/dsh-agent-loop'
 import { mountAgentLoopTestDependencies } from '@deepseek-ai/dsh-agent-loop-testkit'
 import { LocalBashExecutor } from '@deepseek-ai/dsh-bash-local'
+import { SubagentRunId } from '@deepseek-ai/dsh-subagent'
 import * as HooksClaude from '@deepseek-ai/dsh-hooks-claude'
 import { MockAdapter, textResponse, toolCallResponse } from '../../../core/agent-loop/tests/mock-adapter.ts'
 
@@ -231,7 +232,7 @@ export function defineCoverageCases(group: CoverageGroup): void {
       const injected: string[] = []
       const child = { id: SessionId('child-x'), inject: (content: { type: string; text?: string }[]) => { injected.push(content.map(b => b.text ?? '').join('')) }, session: { id: SessionId('child-x'), header: { id: 'child-x' } } } as unknown as Parameters<typeof ctx.agents.register>[0]
       ctx.agents.register(child)
-      ctx.emit('subagent/start', { provider: 'p', id: SessionId('child-x') })
+      ctx.emit('subagent/start', { runId: SubagentRunId('run-x'), provider: 'p', id: SessionId('child-x'), local: true })
       await waitFor(() => injected.includes('child guidance'))
       expect(injected).toContain('child guidance')
     })
@@ -247,7 +248,7 @@ export function defineCoverageCases(group: CoverageGroup): void {
       const warn = vi.fn(); ctx.logger.warn = warn as never
       const child = { id: SessionId('child-y'), inject: () => { throw new Error('inject boom') }, session: { id: SessionId('child-y'), header: { id: 'child-y' } } } as unknown as Parameters<typeof ctx.agents.register>[0]
       ctx.agents.register(child)
-      ctx.emit('subagent/start', { provider: 'p', id: SessionId('child-y') })
+      ctx.emit('subagent/start', { runId: SubagentRunId('run-y'), provider: 'p', id: SessionId('child-y'), local: true })
       await waitFor(() => warn.mock.calls.some(c => String(c[0]).includes('SubagentStart hook failed')))
       expect(warn).toHaveBeenCalledWith(expect.stringContaining('SubagentStart hook failed'))
     })
@@ -291,7 +292,7 @@ export function defineCoverageCases(group: CoverageGroup): void {
       const s = sh(d, 'stop.sh', `#!/usr/bin/env bash\ntouch "${marker}"\n`)
       const path = hooks(d, { SubagentStop: [{ hooks: [{ type: 'command', command: s }] }] })
       const ctx = await harness(path, new MockAdapter([]))
-      ctx.emit('subagent/end', { provider: 'p', id: SessionId('child-z'), stopReason: 'completed' })
+      ctx.emit('subagent/end', { runId: SubagentRunId('run-z'), provider: 'p', id: SessionId('child-z'), local: false, stopReason: 'completed' })
       await waitFor(() => existsSync(marker))
       expect(existsSync(marker)).toBe(true)
     })
@@ -691,7 +692,7 @@ export function defineCoverageCases(group: CoverageGroup): void {
       // Register a live child on its own session cwd; emit subagent/end with its id.
       const { SessionId } = await import('@deepseek-ai/dsh-session')
       const childHandle = await ctx.agents.create({ sessionId: SessionId('child-stop-session'), meta: { cwd: childDir }, agentOptions: { provider: 'mock', model: 'mock' } })
-      ctx.emit('subagent/end', { provider: 'inproc', id: childHandle.agent.id, stopReason: 'completed' })
+      ctx.emit('subagent/end', { runId: SubagentRunId('run-stop'), provider: 'inproc', id: childHandle.agent.id, local: true, stopReason: 'completed' })
 
       await waitFor(() => existsSync(marker))
       expect(existsSync(marker)).toBe(true) // the marker landed in the CHILD dir
diff --git a/packages/subagent/subagent-acp/src/run.ts b/packages/subagent/subagent-acp/src/run.ts
index b7b10ecb97..a10a87a940 100644
--- a/packages/subagent/subagent-acp/src/run.ts
+++ b/packages/subagent/subagent-acp/src/run.ts
@@ -294,6 +294,7 @@ export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpe
   let disposal: Promise<void> | undefined
   return {
     id,
+    localAgent: undefined,
     result,
     dispose(): Promise<void> {
       if (disposal !== undefined) return disposal
diff --git a/packages/subagent/subagent-inprocess/src/index.ts b/packages/subagent/subagent-inprocess/src/index.ts
index 018f93051f..c5c85ec232 100644
--- a/packages/subagent/subagent-inprocess/src/index.ts
+++ b/packages/subagent/subagent-inprocess/src/index.ts
@@ -175,6 +175,7 @@ export async function startInProcessRun(
 
   return {
     id: childId,
+    localAgent: child,
     result,
     dispose(): Promise<void> {
       request.signal.removeEventListener('abort', onAbort)
diff --git a/packages/subagent/subagent/README.md b/packages/subagent/subagent/README.md
index 45e0976ed7..17edd0e3c7 100644
--- a/packages/subagent/subagent/README.md
+++ b/packages/subagent/subagent/README.md
@@ -50,9 +50,9 @@ Runtime features are optional methods on `SubagentRun`: `sendMessage?` steers a
 
 `SubagentRun.result` resolves to `{ output, structured?, stopReason }`. Child-level failures resolve with a non-`completed` reason; only an infrastructure fault that the seam cannot represent may reject. `dispose()` is idempotent, cancels remaining work, and waits for the child resources to quiesce.
 
-A local run publishes an ordinary child agent/session before `start()` fulfills, returns that shared session id as `SubagentRun.id`, and records `request.parent.session.id` in the child's `parentSession` header. The child may be owned by the parent scope or by a provider/root scope; durable lineage is the transport-neutral local-child relation. Remote providers instead mint a parent-scoped lifecycle id without publishing a local child.
+A local run publishes an ordinary child agent/session before `start()` fulfills, returns that shared session id as `SubagentRun.id`, exposes the exact child as `SubagentRun.localAgent`, and records `request.parent.session.id` in the child's `parentSession` header. Remote providers instead mint a parent-scoped lifecycle id and return `localAgent: undefined`.
 
-The service emits `subagent/start` only after `start()` has fulfilled. It attaches the result observer before that synchronous notification, so even an already-settled child still produces `subagent/start` before `subagent/end`. In-process start observers can resolve the published child through `ctx.agents.get(info.id)`; remote providers need not publish a local agent.
+The service emits `subagent/start` only after `start()` has fulfilled. It attaches the result observer before that synchronous notification, so even an already-settled child still produces `subagent/start` before `subagent/end`. The pair shares a service-minted `runId`; its `local` flag is snapshotted from the provider's exact `localAgent`, so observers never infer run identity or locality from reusable provider/session names.
 
 Run events are scoped to the delegating parent. Every listener is independently contained: a synchronous throw or rejected returned promise is logged without starving peer listeners or changing the run.
 
diff --git a/packages/subagent/subagent/package.json b/packages/subagent/subagent/package.json
index 84d2c963d5..aea05553e4 100644
--- a/packages/subagent/subagent/package.json
+++ b/packages/subagent/subagent/package.json
@@ -23,6 +23,7 @@
   "license": "BSD-3-Clause",
   "peerDependencies": {
     "@deepseek-ai/dsh-agent": "^0.0.1",
+    "@deepseek-ai/dsh-brand": "^0.0.1",
     "@deepseek-ai/dsh-llm": "^0.0.1",
     "@deepseek-ai/dsh-scope": "^0.0.1",
     "@deepseek-ai/dsh-session": "^0.0.1",
@@ -31,6 +32,7 @@
   },
   "devDependencies": {
     "@deepseek-ai/dsh-agent": "workspace:^",
+    "@deepseek-ai/dsh-brand": "workspace:^",
     "@deepseek-ai/dsh-llm": "workspace:^",
     "@deepseek-ai/dsh-scope": "workspace:^",
     "@deepseek-ai/dsh-session": "workspace:^",
diff --git a/packages/subagent/subagent/src/index.ts b/packages/subagent/subagent/src/index.ts
index 00762cc413..8f3549ac7c 100644
--- a/packages/subagent/subagent/src/index.ts
+++ b/packages/subagent/subagent/src/index.ts
@@ -28,6 +28,7 @@
  * @module @deepseek-ai/dsh-subagent
  */
 
+import { randomUUID } from 'node:crypto'
 import { Context, Service } from 'cordis'
 import { scopeTarget } from '@deepseek-ai/dsh-scope'
 import type { Scoped } from '@deepseek-ai/dsh-scope'
@@ -43,7 +44,9 @@ import type {
   SubagentRun,
   SubagentStartRequest,
 } from './types.ts'
+import { SubagentRunId } from './types.ts'
 
+export { SubagentRunId } from './types.ts'
 export type {
   SubagentCapabilities,
   SubagentProvider,
@@ -112,18 +115,26 @@ declare module 'cordis' {
 
 /** Observe-only identifying detail for a ready subagent run. */
 export interface SubagentRunInfo {
+  /** Unique identity shared with the paired terminal event. */
+  readonly runId: SubagentRunId
   /** The provider that established the run. */
   readonly provider: string
   /** The child agent's id. */
   readonly id: SessionId
+  /** Whether the provider exposed an exact published in-process child. */
+  readonly local: boolean
 }
 
 /** Observe-only outcome detail for a settled subagent run. */
 export interface SubagentRunEndInfo {
+  /** Unique identity shared with the paired start event. */
+  readonly runId: SubagentRunId
   /** The provider that ran it. */
   readonly provider: string
   /** The child agent's id. */
   readonly id: SessionId
+  /** Whether the provider exposed an exact published in-process child. */
+  readonly local: boolean
   /** The terminal stop reason. */
   readonly stopReason: SubagentResult['stopReason']
   /** The child's final assistant output, absent on infrastructure rejection. */
@@ -208,22 +219,28 @@ export class SubagentService extends Service {
 
     const parent = request.parent
     const run = await provider.start(request)
+    const runId = SubagentRunId(randomUUID())
+    const lifecycleIdentity = {
+      runId,
+      provider: name,
+      id: run.id,
+      local: run.localAgent !== undefined,
+    }
     // Attach the terminal observer before dispatching start. Promise reactions
     // still run after this synchronous start emission, preserving start → end.
     void run.result.then(
       (result) => {
         this.emitLifecycle('subagent/end', {
-          provider: name,
-          id: run.id,
+          ...lifecycleIdentity,
           stopReason: result.stopReason,
           lastAssistantMessage: result.output,
         }, parent)
       },
       () => {
-        this.emitLifecycle('subagent/end', { provider: name, id: run.id, stopReason: 'error' }, parent)
+        this.emitLifecycle('subagent/end', { ...lifecycleIdentity, stopReason: 'error' }, parent)
       },
     )
-    this.emitLifecycle('subagent/start', { provider: name, id: run.id }, parent)
+    this.emitLifecycle('subagent/start', lifecycleIdentity, parent)
     return run
   }
 
diff --git a/packages/subagent/subagent/src/types.ts b/packages/subagent/subagent/src/types.ts
index e5ba8fd84d..1b1645d89b 100644
--- a/packages/subagent/subagent/src/types.ts
+++ b/packages/subagent/subagent/src/types.ts
@@ -7,10 +7,23 @@
  */
 
 import type { Agent, AgentOptions } from '@deepseek-ai/dsh-agent'
+import type { Branded } from '@deepseek-ai/dsh-brand'
 import type { ContentBlock } from '@deepseek-ai/dsh-llm'
 import type { SessionId } from '@deepseek-ai/dsh-session'
 import type { StructuredOutputSchema, ToolRestriction } from '@deepseek-ai/dsh-tools'
 
+/** Identifies one accepted subagent run across its lifecycle event pair. */
+export type SubagentRunId = Branded<'SubagentRunId'>
+
+/**
+ * Brand a string as a {@link SubagentRunId}.
+ * @param id - the raw id string (the service mints UUIDs; tests may pass fixtures).
+ * @returns the same string, branded.
+ */
+export function SubagentRunId(id: string): SubagentRunId {
+  return id as SubagentRunId
+}
+
 /**
  * Which START-TIME features a provider supports. Checked by the service before delegating to
  * {@link SubagentProvider.start}: a request that needs a capability the chosen provider lacks
@@ -139,6 +152,12 @@ export interface SubagentRun {
    * remote provider mints an id unique in the parent namespace.
    */
   readonly id: SessionId
+  /**
+   * The exact published in-process child, or `undefined` for a remote run.
+   * When present, its id is {@link id}; the provider retains no ownership
+   * implication beyond the run's ordinary {@link dispose} contract.
+   */
+  readonly localAgent: Agent | undefined
   /**
    * Resolves with the child's terminal {@link SubagentResult} when the run
    * settles. Does NOT reject on a child-level failure — a model/transport
diff --git a/packages/subagent/subagent/tests/service.spec.ts b/packages/subagent/subagent/tests/service.spec.ts
index ad7dbaafff..66008a923b 100644
--- a/packages/subagent/subagent/tests/service.spec.ts
+++ b/packages/subagent/subagent/tests/service.spec.ts
@@ -48,6 +48,7 @@ class StubProvider implements SubagentProvider {
     this.startCount += 1
     return {
       id: SessionId(`child:${this.name}:${request.parent.id}`),
+      localAgent: undefined,
       result: Promise.resolve(this.outcome),
       async dispose() {},
     }
@@ -137,13 +138,14 @@ describe('SubagentService', () => {
     const parent = fakeParent('delegator')
     const events: string[] = []
     const keys: unknown[] = []
-    ctx.on('subagent/start', function () { events.push('start'); keys.push(carrierKeyOf(this)) })
-    ctx.on('subagent/end', function () { events.push('end'); keys.push(carrierKeyOf(this)) })
+    const runIds: string[] = []
+    ctx.on('subagent/start', function (info) { events.push('start'); keys.push(carrierKeyOf(this)); runIds.push(info.runId) })
+    ctx.on('subagent/end', function (info) { events.push('end'); keys.push(carrierKeyOf(this)); runIds.push(info.runId) })
 
     const starting = subagents.start('deferred', baseRequest({ parent }))
     await Promise.resolve()
     expect(events).toEqual([])
-    ready.resolve({ id: SessionId('child'), result: result.promise, async dispose() {} })
+    ready.resolve({ id: SessionId('child'), localAgent: undefined, result: result.promise, async dispose() {} })
     const run = await starting
     expect(events).toEqual(['start'])
     result.resolve({ output: [{ type: 'text', text: 'answer' }], stopReason: 'completed' })
@@ -151,6 +153,21 @@ describe('SubagentService', () => {
     await Promise.resolve()
     expect(events).toEqual(['start', 'end'])
     expect(keys).toEqual([parent, parent])
+    expect(runIds[0]).toBe(runIds[1])
+  })
+
+  it('mints distinct lifecycle identities when provider and child ids repeat', async () => {
+    const { ctx, subagents } = await service()
+    subagents.registerProvider(new StubProvider('reused'))
+    const runIds: string[] = []
+    ctx.on('subagent/start', info => void runIds.push(info.runId))
+
+    const first = await subagents.start('reused', baseRequest())
+    const second = await subagents.start('reused', baseRequest())
+    await Promise.all([first.result, second.result])
+
+    expect(runIds).toHaveLength(2)
+    expect(new Set(runIds).size).toBe(2)
   })
 
   it('emits no run lifecycle when provider startup rejects', async () => {
@@ -192,7 +209,7 @@ describe('SubagentService', () => {
       capabilities: NO_CAPS,
       inheritsParentContext: false,
       async start() {
-        return { id: SessionId('infra-child'), result: failure.promise, async dispose() {} }
+        return { id: SessionId('infra-child'), localAgent: undefined, result: failure.promise, async dispose() {} }
       },
     })
     const failedRun = await subagents.start('infra', baseRequest())
diff --git a/packages/subagent/tool-subagent/tests/tool-subagent.spec.ts b/packages/subagent/tool-subagent/tests/tool-subagent.spec.ts
index 27a603049e..dbb78812d4 100644
--- a/packages/subagent/tool-subagent/tests/tool-subagent.spec.ts
+++ b/packages/subagent/tool-subagent/tests/tool-subagent.spec.ts
@@ -144,6 +144,7 @@ describe('dsh-tool-subagent', () => {
       inheritsParentContext: false,
       start: async () => ({
         id: SessionId('weird-child'),
+        localAgent: undefined,
         result: Promise.resolve({ output: [{ type: 'text', text: 'partial' }], stopReason: 'frobnicated' as never }),
         dispose: async () => {},
       }),
@@ -171,6 +172,7 @@ describe('dsh-tool-subagent', () => {
         seen = request
         return {
           id: SessionId('capture-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'ok' }], stopReason: 'completed' as const }),
           dispose: async () => {},
         }
@@ -200,6 +202,7 @@ describe('dsh-tool-subagent', () => {
         seen = request
         return {
           id: SessionId('bare-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'ok' }], stopReason: 'completed' as const }),
           dispose: async () => {},
         }
@@ -327,6 +330,7 @@ describe('dsh-tool-subagent', () => {
       inheritsParentContext: false,
       start: async () => ({
         id: SessionId('spy-child'),
+        localAgent: undefined,
         result: Promise.resolve({ output: [{ type: 'text', text: 'ok' }], stopReason: 'completed' as const }),
         dispose: async () => void disposed(),
       }),
@@ -349,6 +353,7 @@ describe('dsh-tool-subagent', () => {
       inheritsParentContext: false,
       start: async () => ({
         id: SessionId('spy-child'),
+        localAgent: undefined,
         result: Promise.resolve({ output: [], stopReason: 'error' as const }),
         dispose: async () => void disposed(),
       }),
@@ -380,6 +385,7 @@ describe('dsh-tool-subagent', () => {
         }, { once: true })
         return {
           id: SessionId('spy-child'),
+          localAgent: undefined,
           result,
           dispose: async () => {},
         }
@@ -472,6 +478,7 @@ describe('dsh-tool-subagent', () => {
         seen = request
         return {
           id: SessionId('capture2-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'ok' }], stopReason: 'completed' as const }),
           dispose: async () => {},
         }
@@ -529,6 +536,7 @@ describe('dsh-tool-subagent', () => {
         seen = request
         return {
           id: SessionId('capture3-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'ok' }], stopReason: 'completed' as const }),
           dispose: async () => {},
         }
@@ -558,6 +566,7 @@ describe('dsh-tool-subagent', () => {
         seen = request
         return {
           id: SessionId('capture4-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'ok' }], stopReason: 'completed' as const }),
           dispose: async () => {},
         }
@@ -732,6 +741,7 @@ describe('dsh-tool-subagent background mode', () => {
         }, { once: true })
         return {
           id,
+          localAgent: undefined,
           result,
           dispose: () => Promise.resolve(),
         }
@@ -771,6 +781,7 @@ describe('dsh-tool-subagent background mode', () => {
     const order: string[] = []
     const completed = await settleRun({
       id: SessionId('child-1'),
+      localAgent: undefined,
       result: Promise.resolve({ output: [{ type: 'text' as const, text: 'ok' }], stopReason: 'completed' as const }),
       dispose() { order.push('dispose'); return Promise.resolve() },
     })
@@ -782,6 +793,7 @@ describe('dsh-tool-subagent background mode', () => {
     let disposed = false
     const failed = await settleRun({
       id: SessionId('child-2'),
+      localAgent: undefined,
       result: Promise.reject(new Error('transport gone')),
       dispose() { disposed = true; return Promise.resolve() },
     })
@@ -790,6 +802,7 @@ describe('dsh-tool-subagent background mode', () => {
 
     const disposeFailed = await settleRun({
       id: SessionId('child-3'),
+      localAgent: undefined,
       result: Promise.resolve({ output: [], stopReason: 'completed' }),
       dispose: () => Promise.reject(new Error('reap failed')),
     })
@@ -797,6 +810,7 @@ describe('dsh-tool-subagent background mode', () => {
 
     const bothFailed = await settleRun({
       id: SessionId('child-4'),
+      localAgent: undefined,
       result: Promise.reject(new Error('result failed')),
       dispose: () => Promise.reject(new Error('reap failed')),
     })
@@ -832,6 +846,7 @@ describe('background preflight failure (no orphaned child, by construction)', ()
         starts += 1
         return {
           id: SessionId('probe-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [], stopReason: 'completed' as const }),
           dispose: () => Promise.resolve(),
         }
diff --git a/packages/support/subagent-mock/src/index.ts b/packages/support/subagent-mock/src/index.ts
index c2e94c521f..4ea30d166a 100644
--- a/packages/support/subagent-mock/src/index.ts
+++ b/packages/support/subagent-mock/src/index.ts
@@ -69,6 +69,7 @@ class MockSubagentProvider implements SubagentProvider {
     })
     return {
       id,
+      localAgent: undefined,
       result,
       dispose(): Promise<void> {
         flags.cancelled = true
diff --git a/packages/ui/jsonrpc/README.md b/packages/ui/jsonrpc/README.md
index 6d9f007e66..3d19b601c4 100644
--- a/packages/ui/jsonrpc/README.md
+++ b/packages/ui/jsonrpc/README.md
@@ -4,7 +4,7 @@ The **SDK server plugin** (`jsonrpc`): mounting it serves a stdio JSON-RPC serve
 
 ## Wiring
 
-`inject: ['agents']`. The server gets or creates one agent per `sessionId` from the `initialize.provider`/`initialize.model` pair. It classifies subagent completions through live parent ownership or durable parent lineage and retains parent-scoped provider/id counts after child disposal. A registered owner for the provider route wins; an unowned `deepseek` route mounts `dsh-llm-deepseek` using `$DEEPSEEK_API_KEY` and `$DEEPSEEK_BASE_URL`, while any other unowned provider fails initialization. Persistence, tools, and other adapters come from the surrounding `cordis.yml`.
+`inject: ['agents']`. The server gets or creates one agent per `sessionId` from the `initialize.provider`/`initialize.model` pair. It forwards subagent completions only when the lifecycle payload's `local` flag was snapshotted from the provider's exact in-process child; reusable provider names, child ids, and durable lineage never establish locality. A registered owner for the provider route wins; an unowned `deepseek` route mounts `dsh-llm-deepseek` using `$DEEPSEEK_API_KEY` and `$DEEPSEEK_BASE_URL`, while any other unowned provider fails initialization. Persistence, tools, and other adapters come from the surrounding `cordis.yml`.
 
 ## Config
 
diff --git a/packages/ui/jsonrpc/src/server.ts b/packages/ui/jsonrpc/src/server.ts
index 91cc49571a..5246795a31 100644
--- a/packages/ui/jsonrpc/src/server.ts
+++ b/packages/ui/jsonrpc/src/server.ts
@@ -19,7 +19,7 @@ import type { Agent, AgentHandle } from '@deepseek-ai/dsh-agent'
 import { carrierKeyOf, type Scoped } from '@deepseek-ai/dsh-scope'
 import { SessionId, type TurnEndReason } from '@deepseek-ai/dsh-session'
 import type SubagentService from '@deepseek-ai/dsh-subagent'
-import type { SubagentRunEndInfo, SubagentRunInfo } from '@deepseek-ai/dsh-subagent'
+import type { SubagentRunEndInfo } from '@deepseek-ai/dsh-subagent'
 import * as LlmDeepSeek from '@deepseek-ai/dsh-llm-deepseek'
 import type { JsonRpcTransportPeer } from './transport.ts'
 
@@ -68,15 +68,6 @@ function subagentParentOf(carrier: Scoped<SubagentService>): Agent {
   return carrierKeyOf(carrier) as Agent
 }
 
-/** Whether the live id names a local child related to this exact delegating parent. */
-function isLocalChild(ctx: Context, id: SessionId, parent: Agent): boolean {
-  const child = ctx.agents.get(id)
-  return child !== undefined && (
-    ctx.agents.isOwnedBy(id, parent)
-    || child.session.header.parentSession === parent.session.id
-  )
-}
-
 /**
  * The SDK server over a booted harness context. Constructing it subscribes to
  * session and subagent lifecycle events, forwarding durable session
@@ -92,7 +83,6 @@ export class HarnessSdkServer {
   private llmFiber: { dispose(): Promise<void> } | undefined
   private readonly sessions = new Map<string, SessionRecord>()
   private readonly sessionCreations = new Map<string, Promise<SessionRecord>>()
-  private readonly localRuns = new Map<string, Map<SessionId, Map<Agent, number>>>()
   private readonly disposers: (() => void)[] = []
   private shutdownTask: Promise<Record<string, never>> | undefined
   private shuttingDown = false
@@ -116,36 +106,12 @@ export class HarnessSdkServer {
         childSessionId: String(session.id),
       })
     }))
-    // In-process providers publish the child before start. Count starts related
-    // by exact runtime ownership or durable parent lineage so provider-owned
-    // roots remain local, completions survive child disposal, and reused ids
-    // need no settlement-order assumption.
-    const localRuns = this.localRuns
-    this.disposers.push(ctx.on('subagent/start', function (this: Scoped<SubagentService>, info: SubagentRunInfo) {
-      const parent = subagentParentOf(this)
-      if (!isLocalChild(ctx, info.id, parent)) return
-      const providerRuns = localRuns.get(info.provider) ?? new Map<SessionId, Map<Agent, number>>()
-      const parentRuns = providerRuns.get(info.id) ?? new Map<Agent, number>()
-      parentRuns.set(parent, (parentRuns.get(parent) ?? 0) + 1)
-      providerRuns.set(info.id, parentRuns)
-      localRuns.set(info.provider, providerRuns)
-    }))
     this.disposers.push(ctx.on('subagent/end', function (this: Scoped<SubagentService>, info: SubagentRunEndInfo) {
       const parent = subagentParentOf(this)
-      const providerRuns = localRuns.get(info.provider)
-      const parentRuns = providerRuns?.get(info.id)
-      const pendingCount = parentRuns?.get(parent)
-      if (pendingCount !== undefined) {
-        if (pendingCount === 1) parentRuns?.delete(parent)
-        else parentRuns?.set(parent, pendingCount - 1)
-        if (parentRuns?.size === 0) providerRuns?.delete(info.id)
-        if (providerRuns?.size === 0) localRuns.delete(info.provider)
-      }
-      // This protocol reports LOCAL child sessions. A lineage-bearing child
-      // has the session/created-driven start notification above. A remote run
-      // has neither a cached local start nor a live child related to this
-      // parent; an unrelated local agent with the same id never makes it local.
-      if (pendingCount === undefined && !isLocalChild(ctx, info.id, parent)) return
+      // This protocol reports only in-process child sessions. The service
+      // snapshots the provider's exact run provenance through child disposal;
+      // matching ids or parent lineage alone never establishes locality.
+      if (!info.local) return
       transport.notify('subagent.finished', {
         provider: info.provider,
         agentId: String(info.id),
@@ -223,7 +189,6 @@ export class HarnessSdkServer {
     this.sessionCreations.clear()
     const records = [...this.sessions.values()]
     this.sessions.clear()
-    this.localRuns.clear()
     const failures: unknown[] = []
     while (this.disposers.length > 0) {
       try {
diff --git a/packages/ui/jsonrpc/tests/built-scope-carrier.e2e.ts b/packages/ui/jsonrpc/tests/built-scope-carrier.e2e.ts
index ed4dfbb9db..54727f571b 100644
--- a/packages/ui/jsonrpc/tests/built-scope-carrier.e2e.ts
+++ b/packages/ui/jsonrpc/tests/built-scope-carrier.e2e.ts
@@ -71,6 +71,7 @@ try {
     start() {
       return Promise.resolve({
         id: child.agent.id,
+        localAgent: child.agent,
         result: result.promise,
         dispose() { return Promise.resolve(); },
       });
diff --git a/packages/ui/jsonrpc/tests/server.spec.ts b/packages/ui/jsonrpc/tests/server.spec.ts
index 3fe73c904e..5b9259dd85 100644
--- a/packages/ui/jsonrpc/tests/server.spec.ts
+++ b/packages/ui/jsonrpc/tests/server.spec.ts
@@ -70,7 +70,7 @@ async function makeHarness(storageDir: string) {
 async function settleSubagent(
   ctx: Context,
   parent: Agent,
-  info: SubagentRunEndInfo,
+  info: Omit<SubagentRunEndInfo, 'runId' | 'local'> & { localAgent: Agent | undefined },
   beforeSettle?: () => Promise<void>,
 ): Promise<void> {
   const result = Promise.withResolvers<SubagentResult>()
@@ -81,6 +81,7 @@ async function settleSubagent(
     async start() {
       return {
         id: info.id,
+        localAgent: info.localAgent,
         result: result.promise,
         dispose: () => Promise.resolve(),
       }
@@ -294,12 +295,14 @@ describe('HarnessSdkServer', () => {
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'spawn',
         id: SessionId('child-session'),
+        localAgent: handle.agent,
         stopReason: 'completed',
         lastAssistantMessage: [{ type: 'text', text: 'child done' }],
       }, () => handle.dispose())
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'spawn',
         id: SessionId('parentless-child-session'),
+        localAgent: parentlessHandle.agent,
         stopReason: 'error',
       }, () => parentlessHandle.dispose())
 
@@ -335,7 +338,7 @@ describe('HarnessSdkServer', () => {
     }
   })
 
-  it('ignores a remote run id that collides with an unrelated local agent', async () => {
+  it('ignores a remote run id that collides with a local child of the same parent', async () => {
     const storageDir = await mkdtemp(join(tmpdir(), 'dsh-jsonrpc-subagent-remote-collision-'))
     const ctx = await makeHarness(storageDir)
     try {
@@ -346,24 +349,26 @@ describe('HarnessSdkServer', () => {
         meta: { cwd: storageDir },
         agentOptions: { model: 'deepseek' },
       })
-      const unrelatedHandle = await ctx.agents.create({
+      const collidingChild = await parentHandle.agent.ctx.agents.create({
         sessionId: SessionId('remote-run-id'),
-        meta: { cwd: storageDir },
+        meta: { cwd: storageDir, parentSession: SessionId('collision-parent') },
         agentOptions: { model: 'deepseek' },
       })
 
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'remote',
         id: SessionId('remote-run-id'),
+        localAgent: undefined,
         stopReason: 'completed',
         lastAssistantMessage: [],
-      }, () => unrelatedHandle.dispose())
+      })
 
       expect(transport.notifications.some(notification =>
         notification.method === 'subagent.finished'
         && notification.params?.agentId === 'remote-run-id',
       )).toBe(false)
 
+      await collidingChild.dispose()
       await parentHandle.dispose()
       await server.shutdown()
     } finally {
@@ -392,12 +397,14 @@ describe('HarnessSdkServer', () => {
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'continuation',
         id: SessionId('continuation-child'),
+        localAgent: childHandle.agent,
         stopReason: 'completed',
         lastAssistantMessage: [{ type: 'text', text: 'first' }],
       })
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'continuation',
         id: SessionId('continuation-child'),
+        localAgent: childHandle.agent,
         stopReason: 'completed',
         lastAssistantMessage: [{ type: 'text', text: 'second' }],
       }, () => childHandle.dispose())
@@ -436,6 +443,7 @@ describe('HarnessSdkServer', () => {
       const replacement = Promise.withResolvers<SubagentResult>()
       const results = [first.promise, sameLifetime.promise, replacement.promise]
       let starts = 0
+      let currentLocalAgent = oldChild.agent
       const disposeProvider = ctx.subagents.registerProvider({
         name: 'reused',
         capabilities: { outputSchema: false, depthLimit: false, toolFilter: false, persona: false },
@@ -444,7 +452,7 @@ describe('HarnessSdkServer', () => {
           const result = results[starts]
           starts += 1
           if (result === undefined) throw new Error('unexpected fourth reused-id run')
-          return Promise.resolve({ id: SessionId('reused-child'), result, dispose: () => Promise.resolve() })
+          return Promise.resolve({ id: SessionId('reused-child'), localAgent: currentLocalAgent, result, dispose: () => Promise.resolve() })
         },
       })
 
@@ -471,6 +479,7 @@ describe('HarnessSdkServer', () => {
         meta: { cwd: storageDir, parentSession: SessionId('new-parent') },
         agentOptions: { model: 'deepseek' },
       })
+      currentLocalAgent = newChild.agent
       const secondRun = await ctx.subagents.start('reused', {
         parent: newParent.agent,
         prompt: [],
@@ -512,7 +521,99 @@ describe('HarnessSdkServer', () => {
     }
   })
 
-  it('falls back to live lineage and ignores runs without a local child session', async () => {
+  it('keeps locality bound to the accepted run across provider re-registration', async () => {
+    const storageDir = await mkdtemp(join(tmpdir(), 'dsh-jsonrpc-subagent-provider-reuse-'))
+    const ctx = await makeHarness(storageDir)
+    try {
+      const transport = new FakeTransport()
+      const server = new HarnessSdkServer(ctx, transport)
+      const parent = await ctx.agents.create({
+        sessionId: SessionId('provider-reuse-parent'),
+        meta: { cwd: storageDir },
+        agentOptions: { model: 'deepseek' },
+      })
+      const child = await parent.agent.ctx.agents.create({
+        sessionId: SessionId('provider-reuse-child'),
+        meta: { cwd: storageDir, parentSession: SessionId('provider-reuse-parent') },
+        agentOptions: { model: 'deepseek' },
+      })
+      const localResult = Promise.withResolvers<SubagentResult>()
+      const remoteResult = Promise.withResolvers<SubagentResult>()
+      const unregisterLocal = ctx.subagents.registerProvider({
+        name: 'reused-provider',
+        capabilities: { outputSchema: false, depthLimit: false, toolFilter: false, persona: false },
+        inheritsParentContext: false,
+        start: () => Promise.resolve({
+          id: SessionId('provider-reuse-child'),
+          localAgent: child.agent,
+          result: localResult.promise,
+          dispose: () => Promise.resolve(),
+        }),
+      })
+      const localRun = await ctx.subagents.start('reused-provider', {
+        parent: parent.agent,
+        prompt: [],
+        signal: new AbortController().signal,
+      })
+      unregisterLocal()
+
+      const unregisterRemote = ctx.subagents.registerProvider({
+        name: 'reused-provider',
+        capabilities: { outputSchema: false, depthLimit: false, toolFilter: false, persona: false },
+        inheritsParentContext: false,
+        start: () => Promise.resolve({
+          id: SessionId('provider-reuse-child'),
+          localAgent: undefined,
+          result: remoteResult.promise,
+          dispose: () => Promise.resolve(),
+        }),
+      })
+      const remoteRun = await ctx.subagents.start('reused-provider', {
+        parent: parent.agent,
+        prompt: [],
+        signal: new AbortController().signal,
+      })
+
+      remoteResult.resolve({ output: [{ type: 'text', text: 'remote' }], stopReason: 'completed' })
+      await remoteRun.result
+      await Promise.resolve()
+      expect(transport.notifications.some(notification =>
+        notification.method === 'subagent.finished'
+        && notification.params?.lastAssistantMessage !== undefined,
+      )).toBe(false)
+
+      await child.dispose()
+      localResult.resolve({ output: [{ type: 'text', text: 'local' }], stopReason: 'completed' })
+      await localRun.result
+      await Promise.resolve()
+      expect(transport.notifications.filter(notification =>
+        notification.method === 'subagent.finished'
+        && notification.params?.childSessionId === 'provider-reuse-child',
+      )).toEqual([{
+        method: 'subagent.finished',
+        params: {
+          provider: 'reused-provider',
+          agentId: 'provider-reuse-child',
+          parentSessionId: 'provider-reuse-parent',
+          childSessionId: 'provider-reuse-child',
+          status: 'ok',
+          stopReason: 'completed',
+          lastAssistantMessage: [{ type: 'text', text: 'local' }],
+        },
+      }])
+
+      await localRun.dispose()
+      await remoteRun.dispose()
+      unregisterRemote()
+      await parent.dispose()
+      await server.shutdown()
+    } finally {
+      await ctx.fiber.dispose()
+      await rm(storageDir, { recursive: true, force: true })
+    }
+  })
+
+  it('uses explicit local provenance when start was missed and ignores remote runs', async () => {
     const storageDir = await mkdtemp(join(tmpdir(), 'dsh-jsonrpc-subagent-fallback-'))
     const ctx = await makeHarness(storageDir)
     let parentHandle: AgentHandle | undefined
@@ -529,6 +630,7 @@ describe('HarnessSdkServer', () => {
         meta: { cwd: storageDir, parentSession: SessionId('fallback-parent') },
         agentOptions: { provider: 'deepseek', model: 'deepseek' },
       })
+      const fallbackChild = handle.agent
       failedHandle = await parentHandle.agent.ctx.agents.create({
         sessionId: SessionId('failed-child-session'),
         meta: { cwd: storageDir },
@@ -541,12 +643,13 @@ describe('HarnessSdkServer', () => {
         inheritsParentContext: true,
         start: () => Promise.resolve({
           id: SessionId('fallback-child-session'),
+          localAgent: fallbackChild,
           result: missedStartResult.promise,
           dispose: () => Promise.resolve(),
         }),
       })
-      // Start before the server subscribes, so the terminal fallback must use
-      // the still-live registry entry rather than a cached start record.
+      // Start before the server subscribes. The terminal payload still carries
+      // this run's exact local child without reconstructing it from ids.
       const missedStartRun = await ctx.subagents.start('fork', {
         parent: parentHandle.agent,
         prompt: [],
@@ -560,22 +663,25 @@ describe('HarnessSdkServer', () => {
       await Promise.resolve()
       await missedStartRun.dispose()
       disposeMissedStartProvider()
-      // The server also missed this agent's creation, but observes the start;
-      // recover its lineage from the still-live registry entry.
+      // The server also missed this agent's creation but sees the exact child
+      // on the run lifecycle payload.
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'fork-live-fallback',
         id: SessionId('fallback-child-session'),
+        localAgent: fallbackChild,
         stopReason: 'completed',
         lastAssistantMessage: [],
       })
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'fork',
         id: SessionId('failed-child-session'),
+        localAgent: failedHandle.agent,
         stopReason: 'error',
       })
       await settleSubagent(ctx, parentHandle.agent, {
         provider: 'fork',
         id: SessionId('missing-child-agent'),
+        localAgent: undefined,
         stopReason: 'error',
       })
 
@@ -800,6 +906,6 @@ describe('HarnessSdkServer', () => {
     const server = new HarnessSdkServer(ctx, new FakeTransport())
 
     await expect(server.shutdown()).rejects.toBe(listenerFailure)
-    expect(on).toHaveBeenCalledTimes(4)
+    expect(on).toHaveBeenCalledTimes(3)
   })
 })
diff --git a/packages/workflow/workflow-workerthread/tests/workflow-workerthread.spec.ts b/packages/workflow/workflow-workerthread/tests/workflow-workerthread.spec.ts
index 5905161e6a..2f52cd7b6b 100644
--- a/packages/workflow/workflow-workerthread/tests/workflow-workerthread.spec.ts
+++ b/packages/workflow/workflow-workerthread/tests/workflow-workerthread.spec.ts
@@ -105,6 +105,7 @@ class StubProvider implements SubagentProvider {
     if (request.signal.aborted) throw new Error('child start aborted before publication')
     return {
       id: SessionId(`stub-child-${index}`),
+      localAgent: undefined,
       result: terminal.promise,
       dispose: () => {
         controlled.disposeCalls += 1
@@ -362,6 +363,7 @@ describe('dsh-workflow-workerthread', () => {
         inheritsParentContext: false,
         start: async () => ({
           id: SessionId('reject-child'),
+          localAgent: undefined,
           result: Promise.reject(new Error('backend exploded')),
           dispose: () => Promise.resolve(),
         }),
@@ -396,6 +398,7 @@ describe('dsh-workflow-workerthread', () => {
       } as unknown as SubagentResult
       const start = vi.spyOn(ctx.subagents, 'start').mockResolvedValue({
         id: SessionId('raw-invalid-child'),
+        localAgent: undefined,
         result: Promise.resolve(invalid),
         dispose: () => Promise.resolve(),
       })
@@ -419,6 +422,7 @@ describe('dsh-workflow-workerthread', () => {
         inheritsParentContext: false,
         start: async () => ({
           id: SessionId('bad-dispose-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'fine' }], stopReason: 'completed' }),
           cancel: () => { /* settled already */ },
           dispose: () => { throw new Error('dispose exploded') },
@@ -440,6 +444,7 @@ describe('dsh-workflow-workerthread', () => {
         inheritsParentContext: false,
         start: async () => ({
           id: SessionId('trap-child'),
+          localAgent: undefined,
           result: Promise.resolve({ output: [{ type: 'text', text: 'fine' }], stopReason: 'completed' }),
           cancel: () => { /* settled already */ },
           // The rejection VALUE's own coercion throws: a warn built with bare
@@ -767,6 +772,7 @@ describe('dsh-workflow-workerthread', () => {
           }, { once: true })
           return {
             id: SessionId('signal-only-child'),
+            localAgent: undefined,
             result,
             dispose: () => Promise.resolve(),
           }
@@ -1088,6 +1094,7 @@ describe('dsh-workflow-workerthread', () => {
 
       ready.resolve({
         id: SessionId('late-ready-child'),
+        localAgent: undefined,
         result: Promise.resolve({ output: [], stopReason: 'aborted' }),
         dispose: () => {
           disposeCalls += 1
@@ -1124,6 +1131,7 @@ describe('dsh-workflow-workerthread', () => {
           }, { once: true })
           return {
             id: SessionId('doomed-child'),
+            localAgent: undefined,
             result: new Promise(() => { /* never settles; the reap is the teardown */ }),
             dispose: () => Promise.reject(new Error('dispose exploded during reap')),
           }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d7b3ab2b95..47d998fedc 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1441,6 +1441,9 @@ importers:
       '@deepseek-ai/dsh-agent':
         specifier: workspace:^
         version: link:../../core/agent
+      '@deepseek-ai/dsh-brand':
+        specifier: workspace:^
+        version: link:../../util/brand
       '@deepseek-ai/dsh-llm':
         specifier: workspace:^
         version: link:../../llm/llm
diff --git a/website/zh-CN/api/harness/events.md b/website/zh-CN/api/harness/events.md
index aafaf28484..1301a6a508 100644
--- a/website/zh-CN/api/harness/events.md
+++ b/website/zh-CN/api/harness/events.md
@@ -383,7 +383,7 @@ A ready child settled. Scope-filtered dispatch uses the same delegating parent c
 
 - `info` — the run identity and terminal outcome.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L109)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L112)
 
 ### subagent/provider-added
 
@@ -397,7 +397,7 @@ A provider became resolvable in the registry.
 
 - `provider` — the registered provider.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L83)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L86)
 
 ### subagent/provider-removed
 
@@ -411,7 +411,7 @@ A provider left the registry. Accepted runs remain holder-owned.
 
 - `name` — the provider name that no longer resolves.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L89)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L92)
 
 ### subagent/start
 
@@ -425,7 +425,7 @@ A provider established a ready child. For in-process providers, `ctx.agents.get(
 
 - `info` — the provider and ready child identity.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L100)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L103)
 
 ## system-prompt/*
 
diff --git a/website/zh-CN/api/harness/subagents.md b/website/zh-CN/api/harness/subagents.md
index 54fe5aa76e..52632e820d 100644
--- a/website/zh-CN/api/harness/subagents.md
+++ b/website/zh-CN/api/harness/subagents.md
@@ -6,7 +6,7 @@
 
 Named provider registry and capability-checked start surface.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L142)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L153)
 
 ### ctx.subagents.registerProvider(provider)
 
@@ -20,7 +20,7 @@ Register a provider under its name. Registration is effect-scoped and HMR safe;
 
 **Returns** the exact Cordis effect disposer.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L156)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L167)
 
 ### ctx.subagents.getProvider(name)
 
@@ -34,7 +34,7 @@ Look up a provider by name.
 
 **Returns** the provider, or undefined when absent.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L179)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L190)
 
 ### ctx.subagents.list()
 
@@ -46,7 +46,7 @@ List registered provider names in insertion order.
 
 **Returns** the registered names.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L187)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L198)
 
 ### ctx.subagents.start(name, request)
 
@@ -61,4 +61,4 @@ Establish a ready child on the named provider. Capability and semantic checks ru
 
 **Returns** the ready holder-owned run.
 
-[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L200)
+[Source](https://github.com/deepseek-harness/deepseek-harness/blob/master/packages/subagent/subagent/src/index.ts#L211)