diff --git a/.project-docs/30-worklog/tasks/20260824-pi-feature-ui-9d4e7a31.md b/.project-docs/30-worklog/tasks/20260824-pi-feature-ui-9d4e7a31.md
index a7bce5a..b64bad3 100644
--- a/.project-docs/30-worklog/tasks/20260824-pi-feature-ui-9d4e7a31.md
+++ b/.project-docs/30-worklog/tasks/20260824-pi-feature-ui-9d4e7a31.md
@@ -97,15 +97,18 @@ Gate result:
 - Windowed streaming thinking DOM output to the latest 16 KB while streaming, restoring the complete text when settled; this keeps the existing REN-008 100 KB pressure budget passing without changing the protocol or test threshold.
 - Isolated Conversation-local async UI state by remounting Header, pending interactions, and the tools inspector on Conversation changes. A pending fork only selects its result while the source project, Agent, and Conversation remain selected; a completed archive no longer clears a newer selection.
 - Added regression coverage for pending fork, archive, interaction response, and tools-load completion across Conversation switches.
+- Bound Conversation metadata writeback to its source project: store upserts now require an explicit project id, fork results are ignored by the current Renderer store after a project switch, and metadata failures are retained under their source project and Conversation instead of the global workspace error.
+- Added project-switch success/failure tests plus Renderer tests proving that old-project forks and metadata errors cannot leak into the newly selected project or Conversation.
 - Updated `README.md` to describe the now-shipped Coding UI state and retained the explicit unverified shared Provider/runtime concurrency boundary.
 
 ## Verification
 
 - `pnpm run typecheck` — Pass.
 - `pnpm run lint:check` — Pass with 0 errors and 6 pre-existing warnings outside PI-130-owned files.
-- Focused PI-130 Vitest coverage — Pass: 17/17 across the two changed UI suites, including facade routes, queue modes/positions, interactions, Conversation controls, metadata and async-switch isolation, nested subagents, compaction retry, inline tool output, fork wording, and removed UI entries.
-- Isolated REN-008 100 KB pressure test — Pass: 20 patch batches, 20 React commits, 34.8 ms Main-to-React p95 against the 50 ms budget. An earlier run was intentionally discarded after it shared CPU with full-repository lint and measured 112.9 ms; the serial full-suite rerun below passed.
-- `pnpm test` — Pass: 219 files; 2332 tests passed; 2 skipped.
+- Focused PI-130 Vitest coverage — Pass: 24/24 across the three changed store/UI suites, including facade routes, queue modes/positions, interactions, Conversation controls, metadata and async-switch isolation, project-switch writeback/error isolation, nested subagents, compaction retry, inline tool output, fork wording, and removed UI entries.
+- Isolated REN-008 100 KB pressure test — Pass: 20 patch batches, 20 React commits, 34.7 ms Main-to-React p95 against the 50 ms budget.
+- Functional full suite without the pressure file, capped at four workers — Pass: 218 files; 2335 tests passed; 2 skipped. Together with the isolated pressure test this covers all 219 files and 2336 passing tests.
+- Default `pnpm test` final reruns — Not recorded as Pass: one 24-worker run lost a Vitest child process without a test stack; the next completed all files but the pressure test measured 57.4 ms while competing with the other workers. Neither run reported a functional assertion failure outside the load-sensitive pressure threshold; the controlled full-suite and isolated-pressure runs above are the acceptance evidence.
 - `pnpm run build:vite` — Pass as part of the scoped Electron E2E command; only existing Vite chunk/dynamic-import warnings were reported.
 - `pnpm run test:e2e -- tests/e2e/pi-coding-first-chat.spec.ts` — Pass: 2/2, covering first-Conversation editability, two Conversation isolation, queue, interaction, model, abort, subagent, files/changes/commands tools, and removed share/revert/todo/global-runtime entries.
 - `git diff --check` — Pass.
diff --git a/src/pages/Chat/CodingChatPanel.tsx b/src/pages/Chat/CodingChatPanel.tsx
index 2bd753f..1d4196c 100644
--- a/src/pages/Chat/CodingChatPanel.tsx
+++ b/src/pages/Chat/CodingChatPanel.tsx
@@ -96,6 +96,9 @@ export function CodingChatPanel({
   const selectedAgentId = useCodingWorkspaceStore((state) => state.selectedAgentId);
   const workspaceLoadState = useCodingWorkspaceStore((state) => state.loadState);
   const workspaceError = useCodingWorkspaceStore((state) => state.error);
+  const conversationErrorsByProjectId = useCodingWorkspaceStore(
+    (state) => state.conversationErrorsByProjectId,
+  );
   const creatingAgentIds = useCodingWorkspaceStore((state) => state.creatingAgentIds);
   const loadWorkspace = useCodingWorkspaceStore((state) => state.load);
   const selectAgent = useCodingWorkspaceStore((state) => state.selectAgent);
@@ -149,6 +152,9 @@ export function CodingChatPanel({
       && !conversation.archivedAt
   )) ?? null;
   const targetConversationId = selectedConversation?.id ?? null;
+  const conversationMetadataError = activeProject && targetConversationId
+    ? conversationErrorsByProjectId[activeProject.id]?.[targetConversationId] ?? null
+    : null;
   const provisionalDraftKey = activeProject && selectedAgent
     ? `new:${activeProject.id}:${selectedAgent.id}`
     : null;
@@ -340,9 +346,10 @@ export function CodingChatPanel({
     const sourceAgentId = selectedAgent.id;
     const sourceConversationId = targetConversationId;
     const forked = await forkCodingConversation(sourceConversationId, sourceEntryId);
-    upsertConversation(forked);
-    primeConversation(createLocalConversationSnapshot(sourceProjectId, forked));
     const workspace = codingWorkspaceStore.getState();
+    if (workspace.activeProjectId !== sourceProjectId) return;
+    upsertConversation(sourceProjectId, forked);
+    primeConversation(createLocalConversationSnapshot(sourceProjectId, forked));
     const selectedId = codingConversationStore.getState().selectedConversationId;
     if (workspace.activeProjectId === sourceProjectId
       && workspace.selectedAgentId === sourceAgentId
@@ -656,10 +663,12 @@ export function CodingChatPanel({
           onOpenSettings={onOpenProjectSettings}
         />
 
-        {(workspaceError || connectionError) && (
+        {(workspaceError || conversationMetadataError || connectionError) && (
           <div className="mx-4 mt-3 flex min-h-10 items-center gap-2 rounded-xl bg-destructive/5 px-3 py-2 text-xs text-destructive sm:mx-5">
             <CircleAlert className="h-4 w-4 shrink-0" aria-hidden="true" />
-            <p className="min-w-0 flex-1 text-pretty">{workspaceError ?? connectionError}</p>
+            <p className="min-w-0 flex-1 text-pretty">
+              {workspaceError ?? conversationMetadataError ?? connectionError}
+            </p>
             {workspaceError && (
               <Button
                 type="button"
diff --git a/src/stores/coding-workspace.ts b/src/stores/coding-workspace.ts
index a7a9479..7954234 100644
--- a/src/stores/coding-workspace.ts
+++ b/src/stores/coding-workspace.ts
@@ -42,6 +42,7 @@ export interface CodingWorkspaceState {
   selectedAgentId: string | null;
   loadState: 'idle' | 'loading' | 'ready' | 'error';
   error: string | null;
+  conversationErrorsByProjectId: Record<string, Record<string, string>>;
   creatingAgentIds: Record<string, true>;
   load(): Promise<void>;
   selectAgent(agentId: string): void;
@@ -51,7 +52,7 @@ export interface CodingWorkspaceState {
     conversationId: string,
     patch: { title?: string; archived?: boolean; unread?: boolean },
   ): Promise<CodingConversationMetadata>;
-  upsertConversation(conversation: CodingConversationMetadata): void;
+  upsertConversation(projectId: string, conversation: CodingConversationMetadata): void;
 }
 
 function enabledAgent(config: CodingProjectConfig | null, agentId: string | null): CodingProjectAgent | null {
@@ -76,6 +77,21 @@ function newestConversation(
     .sort((left, right) => right.updatedAt.localeCompare(left.updatedAt))[0] ?? null;
 }
 
+function withConversationError(
+  errorsByProjectId: Record<string, Record<string, string>>,
+  projectId: string,
+  conversationId: string,
+  message: string | null,
+): Record<string, Record<string, string>> {
+  const next = { ...errorsByProjectId };
+  const projectErrors = { ...(next[projectId] ?? {}) };
+  if (message) projectErrors[conversationId] = message;
+  else delete projectErrors[conversationId];
+  if (Object.keys(projectErrors).length > 0) next[projectId] = projectErrors;
+  else delete next[projectId];
+  return next;
+}
+
 function defaultDependencies(): CodingWorkspaceDependencies {
   return {
     listProjects: listCodingProjects,
@@ -103,6 +119,7 @@ export function createCodingWorkspaceStore(
     selectedAgentId: null,
     loadState: 'idle',
     error: null,
+    conversationErrorsByProjectId: {},
     creatingAgentIds: {},
 
     async load() {
@@ -213,18 +230,36 @@ export function createCodingWorkspaceStore(
     },
 
     async patchConversation(conversationId, patch) {
-      set({ error: null });
+      const sourceProjectId = get().activeProjectId;
+      if (!sourceProjectId) throw new Error('当前没有可用的项目。');
+      set((current) => ({
+        conversationErrorsByProjectId: withConversationError(
+          current.conversationErrorsByProjectId,
+          sourceProjectId,
+          conversationId,
+          null,
+        ),
+      }));
       try {
         const conversation = await deps.patchConversation(conversationId, patch);
-        get().upsertConversation(conversation);
+        get().upsertConversation(sourceProjectId, conversation);
         return conversation;
       } catch (error) {
-        set({ error: error instanceof Error ? error.message : String(error) });
+        const message = error instanceof Error ? error.message : String(error);
+        set((current) => ({
+          conversationErrorsByProjectId: withConversationError(
+            current.conversationErrorsByProjectId,
+            sourceProjectId,
+            conversationId,
+            message,
+          ),
+        }));
         throw error;
       }
     },
 
-    upsertConversation(conversation) {
+    upsertConversation(projectId, conversation) {
+      if (get().activeProjectId !== projectId) return;
       set((current) => ({
         conversations: [
           conversation,
diff --git a/tests/unit/coding-chat-panel.test.tsx b/tests/unit/coding-chat-panel.test.tsx
index e530a2a..b70a2ce 100644
--- a/tests/unit/coding-chat-panel.test.tsx
+++ b/tests/unit/coding-chat-panel.test.tsx
@@ -296,6 +296,91 @@ describe('CodingChatPanel first Conversation', () => {
     expect(codingConversationStore.getState().selectedConversationId).toBe(reviewerConversation.id);
   });
 
+  it('does not write a pending fork into the Renderer store after switching projects', async () => {
+    const forkFlight = deferred<CodingConversationMetadata>();
+    const secondProject = { ...project, id: 'project-2', name: 'Second project' };
+    const secondAgent = { ...agent, id: 'agent-project-2', name: 'Second builder' };
+    const secondConversation = {
+      ...conversation,
+      id: 'conversation-project-2',
+      agentId: secondAgent.id,
+      title: 'Second project conversation',
+    };
+    projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
+    projectApi.config.mockResolvedValue({ project, config });
+    projectApi.conversations.mockResolvedValue([conversation]);
+    conversationApi.events.mockResolvedValue(new FakeEventSource() as unknown as EventSource);
+    conversationApi.recover.mockResolvedValue(undefined);
+    conversationApi.fork.mockReturnValue(forkFlight.promise);
+    const { CodingChatPanel } = await import('@/pages/Chat/CodingChatPanel');
+    const { createLocalConversationSnapshot } = await import('@/pages/Chat/coding-chat-snapshot');
+    const { codingWorkspaceStore } = await import('@/stores/coding-workspace');
+    const { codingConversationStore } = await import('@/stores/coding-conversations');
+    conversationApi.snapshot.mockImplementation(async (conversationId: string) => (
+      createLocalConversationSnapshot(
+        conversationId === secondConversation.id ? secondProject.id : project.id,
+        conversationId === secondConversation.id ? secondConversation : conversation,
+      )
+    ));
+    render(<CodingChatPanel />);
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(conversation.id));
+
+    fireEvent.click(screen.getByRole('button', { name: '创建分支' }));
+    await waitFor(() => expect(conversationApi.fork).toHaveBeenCalledWith(conversation.id, undefined));
+    act(() => {
+      codingWorkspaceStore.setState({
+        activeProjectId: secondProject.id,
+        activeProject: secondProject,
+        config: configForAgents([secondAgent]),
+        conversations: [secondConversation],
+        selectedAgentId: secondAgent.id,
+      });
+      codingConversationStore.setState({ selectedConversationId: secondConversation.id });
+    });
+
+    await act(async () => {
+      forkFlight.resolve({ ...conversation, id: 'conversation-forked', title: 'Old project fork' });
+      await forkFlight.promise;
+    });
+    expect(codingWorkspaceStore.getState().conversations).toEqual([secondConversation]);
+    expect(codingConversationStore.getState().selectedConversationId).toBe(secondConversation.id);
+  });
+
+  it('only shows a metadata error on its originating Conversation', async () => {
+    projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
+    projectApi.config.mockResolvedValue({ project, config: configForAgents([agent, reviewer]) });
+    projectApi.conversations.mockResolvedValue([conversation, reviewerConversation]);
+    conversationApi.events.mockResolvedValue(new FakeEventSource() as unknown as EventSource);
+    conversationApi.recover.mockResolvedValue(undefined);
+    const { CodingChatPanel } = await import('@/pages/Chat/CodingChatPanel');
+    const { createLocalConversationSnapshot } = await import('@/pages/Chat/coding-chat-snapshot');
+    const { codingWorkspaceStore } = await import('@/stores/coding-workspace');
+    const { codingConversationStore } = await import('@/stores/coding-conversations');
+    conversationApi.snapshot.mockImplementation(async (conversationId: string) => (
+      createLocalConversationSnapshot(
+        project.id,
+        conversationId === reviewerConversation.id ? reviewerConversation : conversation,
+      )
+    ));
+    render(<CodingChatPanel />);
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(conversation.id));
+    act(() => {
+      codingWorkspaceStore.setState({
+        conversationErrorsByProjectId: {
+          [project.id]: { [conversation.id]: 'metadata rejected' },
+        },
+      });
+    });
+    expect(await screen.findByText('metadata rejected')).toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole('button', { name: /Reviewer/ }));
+    await waitFor(() => expect(codingConversationStore.getState().selectedConversationId)
+      .toBe(reviewerConversation.id));
+    expect(screen.queryByText('metadata rejected')).not.toBeInTheDocument();
+  });
+
   it('does not clear a newly selected Conversation when an old archive request finishes', async () => {
     const archiveFlight = deferred<CodingConversationMetadata>();
     projectApi.list.mockResolvedValue({ projects: [project], activeProjectId: project.id });
diff --git a/tests/unit/coding-workspace-store.test.ts b/tests/unit/coding-workspace-store.test.ts
index 34e5d89..9bcd9d1 100644
--- a/tests/unit/coding-workspace-store.test.ts
+++ b/tests/unit/coding-workspace-store.test.ts
@@ -69,6 +69,16 @@ function conversation(id: string, agentId: string): CodingConversationMetadata {
   };
 }
 
+function deferred<T>() {
+  let resolve!: (value: T) => void;
+  let reject!: (reason?: unknown) => void;
+  const promise = new Promise<T>((resolvePromise, rejectPromise) => {
+    resolve = resolvePromise;
+    reject = rejectPromise;
+  });
+  return { promise, resolve, reject };
+}
+
 describe('coding workspace store', () => {
   it('loads local project metadata and selects the pinned Agent without touching runtime APIs', async () => {
     const listProjects = vi.fn(async () => ({ projects: [project], activeProjectId: project.id }));
@@ -156,4 +166,78 @@ describe('coding workspace store', () => {
       second,
     ]);
   });
+
+  it('does not write an old project metadata result into the newly active project', async () => {
+    const secondProject = { ...project, id: 'project-2', name: 'Second project' };
+    const firstConversation = conversation('conversation-a', 'agent-a');
+    const secondConversation = conversation('conversation-b', 'agent-b');
+    const patchFlight = deferred<CodingConversationMetadata>();
+    let activeProject = project;
+    const store = createCodingWorkspaceStore({
+      listProjects: vi.fn(async () => ({
+        projects: [project, secondProject],
+        activeProjectId: activeProject.id,
+      })),
+      getConfig: vi.fn(async (projectId: string) => (
+        projectId === project.id
+          ? { project, config: config([agent('agent-a')]) }
+          : { project: secondProject, config: config([agent('agent-b')]) }
+      )),
+      listConversations: vi.fn(async (projectId: string) => (
+        projectId === project.id ? [firstConversation] : [secondConversation]
+      )),
+      createConversation: vi.fn(),
+      patchConversation: vi.fn(() => patchFlight.promise),
+    });
+    await store.getState().load();
+
+    const pendingPatch = store.getState().patchConversation(firstConversation.id, { title: 'Old project title' });
+    activeProject = secondProject;
+    await store.getState().load();
+    patchFlight.resolve({ ...firstConversation, title: 'Old project title' });
+    await pendingPatch;
+
+    expect(store.getState()).toMatchObject({
+      activeProjectId: secondProject.id,
+      conversations: [secondConversation],
+    });
+  });
+
+  it('keeps a metadata rejection on its source project and Conversation', async () => {
+    const secondProject = { ...project, id: 'project-2', name: 'Second project' };
+    const firstConversation = conversation('conversation-a', 'agent-a');
+    const secondConversation = conversation('conversation-b', 'agent-b');
+    const patchFlight = deferred<CodingConversationMetadata>();
+    let activeProject = project;
+    const store = createCodingWorkspaceStore({
+      listProjects: vi.fn(async () => ({
+        projects: [project, secondProject],
+        activeProjectId: activeProject.id,
+      })),
+      getConfig: vi.fn(async (projectId: string) => (
+        projectId === project.id
+          ? { project, config: config([agent('agent-a')]) }
+          : { project: secondProject, config: config([agent('agent-b')]) }
+      )),
+      listConversations: vi.fn(async (projectId: string) => (
+        projectId === project.id ? [firstConversation] : [secondConversation]
+      )),
+      createConversation: vi.fn(),
+      patchConversation: vi.fn(() => patchFlight.promise),
+    });
+    await store.getState().load();
+
+    const pendingPatch = store.getState().patchConversation(firstConversation.id, { title: 'Rejected title' });
+    const rejection = expect(pendingPatch).rejects.toThrow('metadata rejected');
+    activeProject = secondProject;
+    await store.getState().load();
+    patchFlight.reject(new Error('metadata rejected'));
+    await rejection;
+
+    expect(store.getState().error).toBeNull();
+    expect(store.getState().conversationErrorsByProjectId).toEqual({
+      [project.id]: { [firstConversation.id]: 'metadata rejected' },
+    });
+    expect(store.getState().conversationErrorsByProjectId[secondProject.id]).toBeUndefined();
+  });
 });