diff --git a/docs/module-graph.md b/docs/module-graph.md
index e4d0b3367d..8ac71b11cc 100644
--- a/docs/module-graph.md
+++ b/docs/module-graph.md
@@ -179,6 +179,7 @@ flowchart TD
   pkg_workflow --> pkg_agent
   pkg_workflow --> pkg_brand
   pkg_workflow --> pkg_llm
+  pkg_workflow --> pkg_session
   pkg_tools --> pkg_agent
   pkg_tools --> pkg_code_runtime
   pkg_tools --> pkg_llm
@@ -215,6 +216,7 @@ flowchart TD
   pkg_subagent --> pkg_agent
   pkg_subagent --> pkg_llm
   pkg_subagent --> pkg_scope
+  pkg_subagent --> pkg_session
   pkg_subagent --> pkg_tools
   pkg_tool_web --> pkg_llm
   pkg_tool_web --> pkg_system_prompt
@@ -265,6 +267,7 @@ flowchart TD
   pkg_agent_core --> pkg_tools
   pkg_subagent_acp --> pkg_agent
   pkg_subagent_acp --> pkg_llm
+  pkg_subagent_acp --> pkg_session
   pkg_subagent_acp --> pkg_subagent
   pkg_subagent_acp --> pkg_subagent_subprocess
   pkg_subagent_inprocess --> pkg_agent
@@ -285,6 +288,7 @@ flowchart TD
   pkg_hooks_claude --> pkg_tools
   pkg_subagent_mock --> pkg_agent
   pkg_subagent_mock --> pkg_llm
+  pkg_subagent_mock --> pkg_session
   pkg_subagent_mock --> pkg_subagent
   pkg_jsonrpc --> pkg_agent
   pkg_jsonrpc --> pkg_llm
@@ -362,14 +366,14 @@ flowchart TD
 | [`invariants`](../packages/support/invariants) | `support` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`scope`](../packages/core/scope), [`session`](../packages/core/session) |
 | [`user-approval`](../packages/ui/user-approval) | `ui` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`llm`](../packages/llm/llm), [`scope`](../packages/core/scope), [`session`](../packages/core/session), [`system-prompt`](../packages/core/system-prompt) |
 | [`user-interaction`](../packages/ui/user-interaction) | `ui` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm) |
-| [`workflow`](../packages/workflow/workflow) | `workflow` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`llm`](../packages/llm/llm) |
+| [`workflow`](../packages/workflow/workflow) | `workflow` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`llm`](../packages/llm/llm), [`session`](../packages/core/session) |
 | [`tools`](../packages/core/tools) | `core` | [`agent`](../packages/core/agent), [`code-runtime`](../packages/code-runtime/code-runtime), [`llm`](../packages/llm/llm), [`scope`](../packages/core/scope), [`session`](../packages/core/session), [`system-prompt`](../packages/core/system-prompt), [`user-approval`](../packages/ui/user-approval) |
 | [`bash-sandbox`](../packages/bash/bash-sandbox) | `bash` | [`bash`](../packages/bash/bash), [`bash-local`](../packages/bash/bash-local), [`sandbox`](../packages/sandbox/sandbox) |
 | [`agent-loop`](../packages/core/agent-loop) | `core` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`scope`](../packages/core/scope), [`session`](../packages/core/session), [`session-persistence`](../packages/session-persistence/session-persistence), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools) |
 | [`tool-bash`](../packages/bash/tool-bash) | `bash` | [`agent`](../packages/core/agent), [`bash`](../packages/bash/bash), [`llm`](../packages/llm/llm), [`sandbox`](../packages/sandbox/sandbox), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools), [`user-approval`](../packages/ui/user-approval) |
 | [`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-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), [`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) |
 | [`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) |
 | [`timeout-policy`](../packages/timeout/timeout-policy) | `timeout` | [`llm`](../packages/llm/llm), [`timeout`](../packages/util/timeout), [`tools`](../packages/core/tools) |
 | [`tool-todo`](../packages/todo/tool-todo) | `todo` | [`agent`](../packages/core/agent), [`session`](../packages/core/session), [`tools`](../packages/core/tools) |
@@ -380,11 +384,11 @@ flowchart TD
 | [`repeat-tool-guard`](../packages/guard/repeat-tool-guard) | `guard` | [`agent`](../packages/core/agent), [`tools`](../packages/core/tools) |
 | [`tool-workflow`](../packages/workflow/tool-workflow) | `workflow` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools), [`workflow`](../packages/workflow/workflow) |
 | [`agent-core`](../packages/core/agent-core) | `core` | [`agent`](../packages/core/agent), [`agent-loop`](../packages/core/agent-loop), [`invariants`](../packages/support/invariants), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`skill`](../packages/skill/skill), [`skill-local`](../packages/skill/skill-local), [`system-prompt`](../packages/core/system-prompt), [`tool-bash`](../packages/bash/tool-bash), [`tool-skill`](../packages/skill/tool-skill), [`tools`](../packages/core/tools) |
-| [`subagent-acp`](../packages/subagent/subagent-acp) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`subagent`](../packages/subagent/subagent), [`subagent-subprocess`](../packages/subagent/subagent-subprocess) |
+| [`subagent-acp`](../packages/subagent/subagent-acp) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`subagent-subprocess`](../packages/subagent/subagent-subprocess) |
 | [`subagent-inprocess`](../packages/subagent/subagent-inprocess) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`system-prompt`](../packages/core/system-prompt), [`tools`](../packages/core/tools) |
 | [`tool-subagent`](../packages/subagent/tool-subagent) | `subagent` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`subagent`](../packages/subagent/subagent), [`tools`](../packages/core/tools) |
 | [`hooks-claude`](../packages/hooks/hooks-claude) | `hooks` | [`agent`](../packages/core/agent), [`hook-protocol`](../packages/hooks/hook-protocol), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`tools`](../packages/core/tools) |
-| [`subagent-mock`](../packages/support/subagent-mock) | `support` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`subagent`](../packages/subagent/subagent) |
+| [`subagent-mock`](../packages/support/subagent-mock) | `support` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent) |
 | [`jsonrpc`](../packages/ui/jsonrpc) | `ui` | [`agent`](../packages/core/agent), [`llm`](../packages/llm/llm), [`llm-deepseek`](../packages/llm/llm-deepseek), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent) |
 | [`workflow-workerthread`](../packages/workflow/workflow-workerthread) | `workflow` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`llm`](../packages/llm/llm), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`tools`](../packages/core/tools), [`workflow`](../packages/workflow/workflow) |
 | [`subagent-fork`](../packages/subagent/subagent-fork) | `subagent` | [`agent`](../packages/core/agent), [`session`](../packages/core/session), [`subagent`](../packages/subagent/subagent), [`subagent-inprocess`](../packages/subagent/subagent-inprocess) |
diff --git a/docs/rfc/implemented/simplification/2026-06-20-unify-agent-and-session-id.md b/docs/rfc/implemented/simplification/2026-06-20-unify-agent-and-session-id.md
index 79d7332553..bb77717e3b 100644
--- a/docs/rfc/implemented/simplification/2026-06-20-unify-agent-and-session-id.md
+++ b/docs/rfc/implemented/simplification/2026-06-20-unify-agent-and-session-id.md
@@ -14,7 +14,7 @@ Session itself repeated the same fact as `Session.id` and `Session.header.id`. C
 
 ## Decision
 
-An agent's registry id equals its session id. `CreateAgentOptions` accepts one `sessionId` used for both final registry entries; resume registers the agent under `resumeSessionId`; subagent creation mints one combined id; and `Session.id` derives from `header.id`. The existing creation transaction, final-entry collision checks, and exact-entry detach semantics remain; maps and fields whose sole job was translating between the ids are gone.
+An agent's registry id equals its session id. `CreateAgentOptions` accepts one `sessionId` used for both final registry entries; resume registers the agent under `resumeSessionId`; in-process and ACP subagent creation use the child session id; and `Session.id` derives from `header.id`. The existing creation transaction, final-entry collision checks, and exact-entry detach semantics remain; maps and fields whose sole job was translating between the ids are gone.
 
 The config-driven path keeps `agents[].id` as a stable configuration label, not a live routing identity. A fresh start mints the combined id `${label}-session-${randomUUID()}` so durable restarts do not collide; `resumeSessionId` instead supplies the exact combined identity to load and register. Logs may use the stable label while all live and durable lookups use the one `SessionId`.
 
@@ -28,7 +28,7 @@ The config-driven path keeps `agents[].id` as a stable configuration label, not
 
 - Agent create/resume and subagent creation carry one identity, and `Session` stores it in one place.
 - The creation transaction retains final-entry collision, exact-entry detach, rollback, and quiescence coverage without identity-specific lifecycle state.
-- ACP, stdio, hooks, bash ownership, persistence, and lineage use the shared `SessionId` directly. ACP verifies exact `Agent` ownership from the forward session map; JSON-RPC caches only disposable-child parent lineage.
+- ACP, stdio, hooks, bash ownership, persistence, and lineage use the shared `SessionId` directly. The ACP subagent backend uses the child server's returned session id as its run id; the ACP bridge verifies exact `Agent` ownership from the forward session map; and JSON-RPC caches only local disposable-child parent lineage while leaving remote runs outside its local-session notification pair.
 - The config-driven resume-or-create policy is explicit and covered across a durable restart.
 - A production listener search kept `agent/created`/`agent/disposed` and their publication semantics.
 - Typecheck, coverage, snapshots, doc-sync, module-graph verification, build, and hygiene pass.
diff --git a/packages/subagent/subagent-acp/package.json b/packages/subagent/subagent-acp/package.json
index e73d861a79..4c34ebe3fc 100644
--- a/packages/subagent/subagent-acp/package.json
+++ b/packages/subagent/subagent-acp/package.json
@@ -24,6 +24,7 @@
   "peerDependencies": {
     "@deepseek-ai/dsh-agent": "^0.0.1",
     "@deepseek-ai/dsh-llm": "^0.0.1",
+    "@deepseek-ai/dsh-session": "^0.0.1",
     "@deepseek-ai/dsh-subagent": "^0.0.1",
     "@deepseek-ai/dsh-subagent-subprocess": "^0.0.1",
     "cordis": "^4.0.0-rc.6"
@@ -35,6 +36,7 @@
   "devDependencies": {
     "@deepseek-ai/dsh-agent": "workspace:^",
     "@deepseek-ai/dsh-llm": "workspace:^",
+    "@deepseek-ai/dsh-session": "workspace:^",
     "@deepseek-ai/dsh-subagent": "workspace:^",
     "@deepseek-ai/dsh-subagent-subprocess": "workspace:^",
     "@cordisjs/plugin-loader": "^1.0.0-rc.4",
diff --git a/packages/subagent/subagent-acp/src/run.ts b/packages/subagent/subagent-acp/src/run.ts
index 1e82ef85b0..1cc220204f 100644
--- a/packages/subagent/subagent-acp/src/run.ts
+++ b/packages/subagent/subagent-acp/src/run.ts
@@ -23,7 +23,6 @@
  */
 
 import { spawn } from 'node:child_process'
-import { randomUUID } from 'node:crypto'
 import { Readable, Writable } from 'node:stream'
 import {
   ClientSideConnection,
@@ -190,8 +189,6 @@ function toError(value: unknown): Error {
  * @returns the ready run handle for the child subprocess.
  */
 export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpec): Promise<SubagentRun> {
-  const id = SessionId(randomUUID())
-
   if (request.signal.aborted) throw new Error('subagent request was aborted before the ACP child started')
 
   // Spawn the child ACP agent. stdin = ACP request channel, stdout = ACP
@@ -260,7 +257,7 @@ export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpe
     ),
   )
 
-  let sessionId: string | undefined
+  let sessionId: SessionId | undefined
   // Resolves when a cancel is requested, so `result` can settle `aborted` even
   // if the child never cooperates with `session/cancel` (it ignores the notify,
   // or the prompt wedges). The result path races this against the ACP drive: the
@@ -309,7 +306,7 @@ export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpe
           clientCapabilities: {},
         })
         const session = await conn.newSession({ cwd: spec.cwd, mcpServers: [] })
-        sessionId = session.sessionId
+        sessionId = SessionId(session.sessionId)
         if (flags.cancelled) throw new Error('subagent cancelled before the ACP session started')
       })(),
       spawnFailed.then((err): never => { throw err }),
@@ -321,6 +318,11 @@ export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpe
     if (flags.cancelled) throw new Error('subagent request was aborted before the ACP child started')
     throw toError(error)
   }
+  // The startup race can fulfill only after newSession assigned the id; this
+  // guard keeps that cross-closure invariant explicit for TypeScript.
+  /* v8 ignore next */
+  if (sessionId === undefined) throw new Error('ACP child published without a session id')
+  const runId = sessionId
 
   const result: Promise<SubagentResult> = (async (): Promise<SubagentResult> => {
     try {
@@ -332,7 +334,7 @@ export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpe
       // succeeds, transport/process failure rejects the in-flight prompt RPC.
       const prompt = async (): Promise<SubagentResult> => {
         // The startup phase cannot fulfill without assigning the session id.
-        const promptResult = await conn.prompt({ sessionId: sessionId as string, prompt: toAcpPrompt(request.prompt) })
+        const promptResult = await conn.prompt({ sessionId: runId, prompt: toAcpPrompt(request.prompt) })
         return { output: collectOutput(), stopReason: acpStopReason(promptResult.stopReason) }
       }
       return await Promise.race([
@@ -366,7 +368,7 @@ export async function startAcpRun(request: SubagentStartRequest, spec: AcpRunSpe
 
   let disposal: Promise<void> | undefined
   return {
-    id,
+    id: runId,
     result,
     dispose(): Promise<void> {
       if (disposal !== undefined) return disposal
diff --git a/packages/subagent/subagent-acp/tests/mock-acp-server.ts b/packages/subagent/subagent-acp/tests/mock-acp-server.ts
index fb200f3505..5145941526 100644
--- a/packages/subagent/subagent-acp/tests/mock-acp-server.ts
+++ b/packages/subagent/subagent-acp/tests/mock-acp-server.ts
@@ -99,7 +99,7 @@ function makeAgent(conn: AgentSideConnection): Agent {
         writeFileSync(NEWSESSION_GATE.ready, 'at-newSession')
         while (!existsSync(NEWSESSION_GATE.go)) await new Promise(r => setTimeout(r, 10))
       }
-      return { sessionId: randomUUID() }
+      return { sessionId: process.env.MOCK_SESSION_ID ?? randomUUID() }
     },
     authenticate(_params: AuthenticateRequest): Promise<void> {
       // No auth methods advertised; nothing to do.
diff --git a/packages/subagent/subagent-acp/tests/subagent-acp.spec.ts b/packages/subagent/subagent-acp/tests/subagent-acp.spec.ts
index eed3cfe1ed..115d5c3e97 100644
--- a/packages/subagent/subagent-acp/tests/subagent-acp.spec.ts
+++ b/packages/subagent/subagent-acp/tests/subagent-acp.spec.ts
@@ -122,8 +122,9 @@ describe('buildChildEnv', () => {
 
 describe('dsh-subagent-acp', () => {
   it('drives a child process to completion and returns its streamed output', async () => {
-    const ctx = await setup({ MOCK_TEXT: 'hello from acp child', MOCK_STOP: 'end_turn' })
+    const ctx = await setup({ MOCK_TEXT: 'hello from acp child', MOCK_STOP: 'end_turn', MOCK_SESSION_ID: 'acp-child-session' })
     const run = await ctx.subagents.start('acp', request('do X'))
+    expect(run.id).toBe('acp-child-session')
     const result = await run.result
     expect(result.stopReason).toBe('completed')
     expect(text(result.output)).toBe('hello from acp child')
diff --git a/packages/subagent/subagent/package.json b/packages/subagent/subagent/package.json
index eb0dbf8da0..cf1ebf9485 100644
--- a/packages/subagent/subagent/package.json
+++ b/packages/subagent/subagent/package.json
@@ -25,6 +25,7 @@
     "@deepseek-ai/dsh-agent": "^0.0.1",
     "@deepseek-ai/dsh-llm": "^0.0.1",
     "@deepseek-ai/dsh-scope": "^0.0.1",
+    "@deepseek-ai/dsh-session": "^0.0.1",
     "@deepseek-ai/dsh-tools": "^0.0.1",
     "cordis": "^4.0.0-rc.6"
   },
@@ -32,6 +33,7 @@
     "@deepseek-ai/dsh-agent": "workspace:^",
     "@deepseek-ai/dsh-llm": "workspace:^",
     "@deepseek-ai/dsh-scope": "workspace:^",
+    "@deepseek-ai/dsh-session": "workspace:^",
     "@deepseek-ai/dsh-tools": "workspace:^",
     "cordis": "^4.0.0-rc.6"
   }
diff --git a/packages/support/subagent-mock/package.json b/packages/support/subagent-mock/package.json
index 8980cc35d2..528691daef 100644
--- a/packages/support/subagent-mock/package.json
+++ b/packages/support/subagent-mock/package.json
@@ -24,6 +24,7 @@
   "peerDependencies": {
     "@deepseek-ai/dsh-agent": "^0.0.1",
     "@deepseek-ai/dsh-llm": "^0.0.1",
+    "@deepseek-ai/dsh-session": "^0.0.1",
     "@deepseek-ai/dsh-subagent": "^0.0.1",
     "cordis": "^4.0.0-rc.6"
   },
@@ -33,6 +34,7 @@
   "devDependencies": {
     "@deepseek-ai/dsh-agent": "workspace:^",
     "@deepseek-ai/dsh-llm": "workspace:^",
+    "@deepseek-ai/dsh-session": "workspace:^",
     "@deepseek-ai/dsh-subagent": "workspace:^",
     "@cordisjs/plugin-loader": "^1.0.0-rc.4",
     "cordis": "^4.0.0-rc.6"
diff --git a/packages/ui/jsonrpc/README.md b/packages/ui/jsonrpc/README.md
index 933023a2d9..2324227ff7 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 creates one agent per SDK `sessionId` (get-or-create on `session/prompt`). A subagent's shared agent/session id supplies `subagent.finished.childSessionId` directly; the server caches only parent lineage because the child may be disposed before `subagent/end`. The LLM seam is read opportunistically via `ctx.get('llm')` (not injected): when `initialize.model` has no registered adapter, the plugin mounts `dsh-llm-deepseek` for it (credentials from `$DEEPSEEK_API_KEY` / `$DEEPSEEK_BASE_URL`); a config-registered adapter for the model wins. Everything else — persistence, the tool stacks, the adapter set — comes from the surrounding `cordis.yml`.
+`inject: ['agents']` — the server creates one agent per SDK `sessionId` (get-or-create on `session/prompt`). A local subagent's shared agent/session id supplies `subagent.finished.childSessionId` directly; the server caches only parent lineage because the child may be disposed before `subagent/end`. Runs from remote providers are not reported through this local-session notification pair because they create no local `session/created`/`subagent.started` edge. The LLM seam is read opportunistically via `ctx.get('llm')` (not injected): when `initialize.model` has no registered adapter, the plugin mounts `dsh-llm-deepseek` for it (credentials from `$DEEPSEEK_API_KEY` / `$DEEPSEEK_BASE_URL`); a config-registered adapter for the model wins. Everything else — persistence, the tool stacks, the adapter set — comes from the surrounding `cordis.yml`.
 
 ## Config
 
diff --git a/packages/ui/jsonrpc/src/server.ts b/packages/ui/jsonrpc/src/server.ts
index cfa083c394..3c803a6c8c 100644
--- a/packages/ui/jsonrpc/src/server.ts
+++ b/packages/ui/jsonrpc/src/server.ts
@@ -104,8 +104,14 @@ export class HarnessSdkServer {
     }))
     this.disposers.push(ctx.on('subagent/end', (info: SubagentRunEndInfo) => {
       const agent = this.ctx.agents.get(info.id)
-      const parentSessionId = this.subagentParents.get(info.id) ?? agent?.session.header.parentSession
+      const cachedParentSessionId = this.subagentParents.get(info.id)
       this.subagentParents.delete(info.id)
+      // This protocol reports LOCAL child sessions, paired with the
+      // session/created-driven subagent.started notification above. A remote
+      // provider may use a real remote SessionId for its run, but that session
+      // does not exist in this harness and therefore has no paired start event.
+      if (cachedParentSessionId === undefined && agent === undefined) return
+      const parentSessionId = cachedParentSessionId ?? agent?.session.header.parentSession
       this.transport.notify('subagent.finished', {
         provider: info.provider,
         agentId: String(info.id),
diff --git a/packages/ui/jsonrpc/tests/server.spec.ts b/packages/ui/jsonrpc/tests/server.spec.ts
index 433119e046..e7f591b88f 100644
--- a/packages/ui/jsonrpc/tests/server.spec.ts
+++ b/packages/ui/jsonrpc/tests/server.spec.ts
@@ -303,7 +303,7 @@ describe('HarnessSdkServer', () => {
     }
   })
 
-  it('falls back to live lineage and treats the shared id as the child session id', async () => {
+  it('falls back to live lineage and ignores runs without a local child session', async () => {
     const storageDir = await mkdtemp(join(tmpdir(), 'dsh-jsonrpc-subagent-fallback-'))
     const ctx = await makeHarness(storageDir)
     let parentHandle: AgentHandle | undefined
@@ -367,16 +367,10 @@ describe('HarnessSdkServer', () => {
           stopReason: 'error',
         },
       })
-      expect(transport.notifications).toContainEqual({
-        method: 'subagent.finished',
-        params: {
-          provider: 'fork',
-          agentId: 'missing-child-agent',
-          childSessionId: 'missing-child-agent',
-          status: 'error',
-          stopReason: 'error',
-        },
-      })
+      expect(transport.notifications.some(n =>
+        n.method === 'subagent.finished'
+        && n.params?.agentId === 'missing-child-agent',
+      )).toBe(false)
 
       await server.shutdown()
     } finally {
diff --git a/packages/workflow/workflow/package.json b/packages/workflow/workflow/package.json
index a6c004d6d0..4d79d672a1 100644
--- a/packages/workflow/workflow/package.json
+++ b/packages/workflow/workflow/package.json
@@ -25,6 +25,7 @@
     "@deepseek-ai/dsh-agent": "^0.0.1",
     "@deepseek-ai/dsh-brand": "^0.0.1",
     "@deepseek-ai/dsh-llm": "^0.0.1",
+    "@deepseek-ai/dsh-session": "^0.0.1",
     "cordis": "^4.0.0-rc.6"
   },
   "devDependencies": {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d02b4a9ca6..6214564eae 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -827,6 +827,9 @@ importers:
       '@deepseek-ai/dsh-scope':
         specifier: workspace:^
         version: link:../../core/scope
+      '@deepseek-ai/dsh-session':
+        specifier: workspace:^
+        version: link:../../core/session
       '@deepseek-ai/dsh-tools':
         specifier: workspace:^
         version: link:../../core/tools
@@ -852,6 +855,9 @@ importers:
       '@deepseek-ai/dsh-llm':
         specifier: workspace:^
         version: link:../../llm/llm
+      '@deepseek-ai/dsh-session':
+        specifier: workspace:^
+        version: link:../../core/session
       '@deepseek-ai/dsh-subagent':
         specifier: workspace:^
         version: link:../subagent
@@ -1085,6 +1091,9 @@ importers:
       '@deepseek-ai/dsh-llm':
         specifier: workspace:^
         version: link:../../llm/llm
+      '@deepseek-ai/dsh-session':
+        specifier: workspace:^
+        version: link:../../core/session
       '@deepseek-ai/dsh-subagent':
         specifier: workspace:^
         version: link:../../subagent/subagent