feat(composer): move role picker into the input and keep it per conversation

Show the selected role as a compact chip in the input's top-left corner, persist the choice per conversation, and snapshot it on replies so the timeline shows the role as a caption under GoodBuddy.

src/main/assistant/assistant-database.test.ts

@@ -134,6 +134,27 @@ it('persists the story graph switch per conversation without schema migration or
   } finally { database.close() }
 })
 
+it('persists the composer role per conversation and the role snapshot on replies', async () => {
+  const database = await createDatabase()
+  const expertId = randomUUID()
+  const header = { id: randomUUID(), title: 'Role preference', updatedAt: 1000, selectedExpertId: expertId }
+  const team = { id: randomUUID(), title: 'Team preference', updatedAt: 1000, selectedExpertId: 'team' as const }
+  const plain = { id: randomUUID(), title: 'No preference', updatedAt: 1000 }
+  const reply = { id: randomUUID(), role: 'assistant' as const, content: 'Reviewed', state: 'complete' as const,
+    createdAt: 900, expert: { kind: 'expert' as const, id: expertId, name: '代码审查专家' } }
+  try {
+    database.saveLocalConversations([{ header, messages: [reply] }, { header: team, messages: [] }, { header: plain, messages: [] }])
+    database.close()
+    database.initialize('C:\\Workspace')
+    expect(database.getConversation(header.id)).toMatchObject({ selectedExpertId: expertId, messages: [{ expert: reply.expert }] })
+    expect(database.getConversation(team.id).selectedExpertId).toBe('team')
+    expect(database.getConversation(plain.id).selectedExpertId).toBeUndefined()
+    database.saveLocalConversations([{ header: { ...header, selectedExpertId: undefined, updatedAt: 1001 }, messages: [] }])
+    expect(database.getConversation(header.id).selectedExpertId).toBeUndefined()
+    expect(localConversationHeaderSchema.safeParse({ ...plain, selectedExpertId: 'not-an-id' }).success).toBe(false)
+  } finally { database.close() }
+})
+
 it('persists conversation pins without changing timestamps or allowing autosaves to overwrite them', async () => {
   const database = await createDatabase()
   const header = { id: randomUUID(), title: 'Pinned conversation', updatedAt: 1000 }

src/main/assistant/assistant-database.ts

@@ -364,6 +364,7 @@ type MessageMetadata = {
   contextCompressions?: ConversationSnapshot['messages'][number]['contextCompressions']
   tools?: ConversationSnapshot['messages'][number]['tools']
   subagents?: ConversationSnapshot['messages'][number]['subagents']
+  expert?: ConversationMessage['expert']
   sources?: string[]
   sourceReferences?: ConversationSnapshot['messages'][number]['sourceReferences']
   knowledgeRetrieval?: ConversationSnapshot['messages'][number]['knowledgeRetrieval']
@@ -1238,6 +1239,7 @@ const conversationContextStateSchema = conversationSnapshotSchema.pick({
   knowledgeLibraryIds: true,
   knowledgeRetrievalMode: true,
   storyGraphEnabled: true,
+  selectedExpertId: true,
   contextMetrics: true,
   contextCompressionState: true
 })
@@ -1246,7 +1248,7 @@ function parseConversationContextState(
   value: string | null
 ): Pick<
   ConversationSnapshot,
-  'knowledgeLibraryIds' | 'knowledgeRetrievalMode' | 'storyGraphEnabled' | 'contextMetrics' | 'contextCompressionState'
+  'knowledgeLibraryIds' | 'knowledgeRetrievalMode' | 'storyGraphEnabled' | 'selectedExpertId' | 'contextMetrics' | 'contextCompressionState'
 > {
   if (!value) {
     return {}
@@ -1264,18 +1266,20 @@ function parseConversationContextState(
 function serializeConversationContextState(
   conversation: Pick<
     ConversationSnapshot,
-    'knowledgeLibraryIds' | 'knowledgeRetrievalMode' | 'storyGraphEnabled' | 'contextMetrics' | 'contextCompressionState'
+    'knowledgeLibraryIds' | 'knowledgeRetrievalMode' | 'storyGraphEnabled' | 'selectedExpertId' | 'contextMetrics' | 'contextCompressionState'
   >
 ): string | null {
   return conversation.knowledgeLibraryIds !== undefined ||
     conversation.knowledgeRetrievalMode !== undefined ||
     conversation.storyGraphEnabled !== undefined ||
+    conversation.selectedExpertId !== undefined ||
     conversation.contextMetrics ||
     conversation.contextCompressionState
     ? JSON.stringify({
         knowledgeLibraryIds: conversation.knowledgeLibraryIds,
         knowledgeRetrievalMode: conversation.knowledgeRetrievalMode,
         storyGraphEnabled: conversation.storyGraphEnabled,
+        selectedExpertId: conversation.selectedExpertId,
         contextMetrics: conversation.contextMetrics,
         contextCompressionState: conversation.contextCompressionState
       })
@@ -1346,6 +1350,7 @@ function toConversationSnapshot(
         contextCompressions: metadata.contextCompressions,
         tools: metadata.tools,
         subagents: metadata.subagents,
+        expert: metadata.expert,
         sources: metadata.sources,
         sourceReferences: metadata.sourceReferences,
         knowledgeRetrieval: metadata.knowledgeRetrieval,
@@ -1377,6 +1382,7 @@ function serializeConversationMessageMetadata(
     contextCompressions: message.contextCompressions,
     tools: message.tools,
     subagents: message.subagents,
+    expert: message.expert,
     sources: message.sources,
     sourceReferences: message.sourceReferences,
     knowledgeRetrieval: message.knowledgeRetrieval,
@@ -1784,6 +1790,7 @@ function storedRemoteAssistantMessage(
     contextCompressions: metadata.contextCompressions,
     tools: metadata.tools,
     subagents: metadata.subagents,
+    expert: metadata.expert,
     sources: metadata.sources,
     sourceReferences: metadata.sourceReferences,
     knowledgeRetrieval: metadata.knowledgeRetrieval,
@@ -5638,6 +5645,7 @@ export class AssistantDatabase {
         contextCompressions: metadata.contextCompressions,
         tools: metadata.tools,
         subagents: metadata.subagents,
+        expert: metadata.expert,
         sources: metadata.sources,
         sourceReferences: metadata.sourceReferences,
         knowledgeRetrieval: metadata.knowledgeRetrieval,

src/renderer/src/App.test.tsx

@@ -8751,13 +8751,16 @@ describe("App", () => {
     const conversationSettings = within(composer!).getByRole("group", {
       name: "对话设置",
     });
-    // Order: context sources, expert, Runtime, then Runtime-specific settings.
+    // The role chip sits in the input's top-left corner, before the textarea.
+    const inputArea = composer!.querySelector<HTMLElement>(".composer__input")!;
+    const expertTrigger = within(inputArea).getByRole("button", { name: "专家角色：通用助手" });
+    expect(expertTrigger.compareDocumentPosition(screen.getByLabelText("向 GoodBuddy 提问")) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+    expect(within(conversationSettings).queryByRole("button", { name: "专家角色：通用助手" })).not.toBeInTheDocument();
+    // Toolbar order: context sources, Runtime, then Runtime-specific settings.
     const contextTrigger = within(conversationSettings).getByRole("button", { name: "故事图谱与知识库" });
-    const expertTrigger = within(conversationSettings).getByRole("button", { name: "专家角色：通用助手" });
     const runtimeTrigger = within(conversationSettings).getByRole("button", { name: /默认模型/u });
     expect(contextTrigger).toHaveAttribute("aria-expanded", "false");
-    expect(contextTrigger.compareDocumentPosition(expertTrigger) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+    expect(contextTrigger.compareDocumentPosition(runtimeTrigger) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
-    expect(expertTrigger.compareDocumentPosition(runtimeTrigger) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
     expect(
       within(conversationSettings).queryByRole("button", {
         name: /工作模式/u,
@@ -12583,7 +12586,8 @@ describe("App", () => {
 
   it("can dispatch a request to the parallel expert team", async () => {
     render(<App />);
-
+    // The role belongs to the loaded conversation.
+    await screen.findByLabelText("发送");
     selectComposerOption("专家角色", "专家团队（并行）");
     fireEvent.change(screen.getByLabelText("向 GoodBuddy 提问"), {
       target: { value: "制定发布计划" },
@@ -12671,6 +12675,43 @@ describe("App", () => {
     );
   });
 
+  it("keeps the role per conversation and snapshots it on the reply", async () => {
+    const expertId = "00000000-0000-4000-8000-000000000511";
+    vi.mocked(api.experts.list).mockResolvedValueOnce([
+      {
+        id: expertId,
+        name: "审查专家",
+        description: "代码审查",
+        systemInstructions: "Review code.",
+        routingKeywords: [],
+        enabled: true,
+        createdAt: "2026-08-01T00:00:00.000Z",
+        updatedAt: "2026-08-01T00:00:00.000Z",
+      },
+    ]);
+    const { container } = render(<App />);
+    await waitFor(() => expect(api.experts.list).toHaveBeenCalled());
+    const firstTitle = container.querySelector(".conversation-item--active .conversation-item__title")?.textContent;
+    const expertMenu = openComposerMenu("专家角色");
+    fireEvent.click(
+      (await within(expertMenu).findByText("审查专家", { selector: "span" })).closest<HTMLButtonElement>("button")!,
+    );
+    expect(composerMenuTrigger("专家角色")).toHaveAccessibleName("专家角色：审查专家");
+
+    fireEvent.change(screen.getByLabelText("向 GoodBuddy 提问"), { target: { value: "审查这个改动" } });
+    fireEvent.click(screen.getByLabelText("发送"));
+    await waitFor(() => expect(run).toHaveBeenCalledWith(expect.objectContaining({ expertId })));
+    expect(await screen.findByText("审查专家", { selector: ".message__role" })).toBeVisible();
+
+    const create = screen.getAllByRole("button", { name: "新建对话" })[0]!;
+    fireEvent.click(create);
+    await waitFor(() => expect(composerMenuTrigger("专家角色")).toHaveAccessibleName("专家角色：通用助手"));
+
+    fireEvent.click(within(container.querySelector<HTMLElement>(".conversation-list")!)
+      .getByTitle(firstTitle && firstTitle !== "新对话" ? firstTitle : "审查这个改动"));
+    await waitFor(() => expect(composerMenuTrigger("专家角色")).toHaveAccessibleName("专家角色：审查专家"));
+  });
+
   it("shows Subagent states and records child expert activity", async () => {
     render(<App />);
     fireEvent.change(await screen.findByLabelText("向 GoodBuddy 提问"), {

src/renderer/src/App.tsx

@@ -842,6 +842,7 @@ function toConversationSnapshots(
       knowledgeLibraryIds: conversation.knowledgeLibraryIds,
       knowledgeRetrievalMode: conversation.knowledgeRetrievalMode,
       storyGraphEnabled: conversation.storyGraphEnabled,
+      selectedExpertId: conversation.selectedExpertId,
       contextMetrics: conversation.contextMetrics,
       contextCompressionState: conversation.contextCompressionState,
       ...(conversation.branch ? { branch: conversation.branch } : {}),
@@ -1153,7 +1154,6 @@ function App(): React.JSX.Element {
   const [assistantExperts, setAssistantExperts] = useState<AssistantExpert[]>(
     [],
   );
-  const [selectedExpertId, setSelectedExpertId] = useState("");
   const [activeProjectId, setActiveProjectId] = useState("");
   const activeProjectIdRef = useRef(activeProjectId);
   const workspaceChangesRequestRef = useRef(0);
@@ -2280,6 +2280,34 @@ function App(): React.JSX.Element {
   // Header fields of the active conversation, value-compared: message updates
   // (streaming flushes, tool events) do not re-render App.
   const activeConversation = useActiveConversationView(conversationStore, activeId);
+  // The role follows the conversation; a deleted role reads as the general
+  // assistant.
+  const resolveExpertSelection = useCallback(
+    (value: string | undefined): string =>
+      !value || value === "team" ||
+      assistantExperts.some((expert) => expert.id === value)
+        ? value ?? ""
+        : "",
+    [assistantExperts],
+  );
+  const selectedExpertId = resolveExpertSelection(activeConversation?.selectedExpertId);
+  const setSelectedExpertId = useCallback(
+    (value: string): void => {
+      setConversations((current) =>
+        current.map((conversation) =>
+          conversation.id === activeId &&
+          (conversation.selectedExpertId ?? "") !== value
+            ? {
+                ...conversation,
+                selectedExpertId: value ? value : undefined,
+                updatedAt: Date.now(),
+              }
+            : conversation,
+        ),
+      );
+    },
+    [activeId, setConversations],
+  );
   const enabledKnowledgeLibraryIds =
     activeConversation?.knowledgeLibraryIds ?? [];
   const setEnabledKnowledgeLibraryIds = useCallback(
@@ -5113,7 +5141,7 @@ function App(): React.JSX.Element {
         : (queuedInput.expertId ?? "")
       : runtime?.capability === "image-generation"
         ? ""
-        : selectedExpertId;
+        : resolveExpertSelection(conversationSnapshot.selectedExpertId);
     const knowledgeLibraryIdsSnapshot =
       queuedInput?.knowledgeLibraryIds ?? enabledKnowledgeLibraryIds;
     const smartRoutingSnapshot =
@@ -5210,6 +5238,14 @@ function App(): React.JSX.Element {
     const executionPrompt = memoryContext
       ? `${prompt}\n\n${memoryContext}`
       : prompt;
+    const selectedExpert = selectedExpertSnapshot && selectedExpertSnapshot !== "team"
+      ? assistantExperts.find((expert) => expert.id === selectedExpertSnapshot)
+      : undefined;
+    const expertSnapshot: Message["expert"] = selectedExpertSnapshot === "team"
+      ? { kind: "team" }
+      : selectedExpert
+        ? { kind: "expert", id: selectedExpert.id, name: selectedExpert.name.trim().slice(0, 80) }
+        : undefined;
     const assistantMessage: Message = {
       id: crypto.randomUUID(),
       role: "assistant",
@@ -5218,6 +5254,7 @@ function App(): React.JSX.Element {
       createdAt: Date.now(),
       state: "streaming",
       status: t("chat.status.preparingRequest"),
+      ...(expertSnapshot ? { expert: expertSnapshot } : {}),
     };
 
     activeRuns.current.set(requestId, {
@@ -6512,16 +6549,10 @@ function App(): React.JSX.Element {
     onClose: () => {
       commitView(viewRef.current);
     },
+    // Each conversation keeps its role; one that no longer resolves reads as
+    // the general assistant (see resolveExpertSelection).
     onExpertsChanged: (experts: AssistantExpert[]) => {
       setAssistantExperts(experts);
-      if (
-        (selectedExpertId === "team" && experts.length < 2) ||
-        (selectedExpertId &&
-          selectedExpertId !== "team" &&
-          !experts.some((expert) => expert.id === selectedExpertId))
-      ) {
-        setSelectedExpertId("");
-      }
     },
     onRemoteProjectsEnabledChange: handleRemoteProjectsEnabledChange,
     onProjectsDeleted: removeProjectsFromUi,

src/renderer/src/ChatTimeline.test.tsx

@@ -180,6 +180,23 @@ describe('ChatTimeline', () => {
     }
   })
 
+  it('keeps the GoodBuddy name and shows the saved role as a caption below it', () => {
+    const props = { ...callbacks, artifactById: new Map(), conversationId: 'role', hiddenMessageCount: 0,
+      isUnusedConversation: false, locale: 'zh-CN' as const, messageStartIndex: 0, totalMessageCount: 3 }
+    const messages: Message[] = [
+      { id: 'expert', role: 'assistant', content: 'a', createdAt: 1, state: 'complete',
+        expert: { kind: 'expert', id: '00000000-0000-4000-8000-000000000901', name: '代码审查专家' } },
+      { id: 'team', role: 'assistant', content: 'b', createdAt: 2, state: 'complete', expert: { kind: 'team' } },
+      { id: 'plain', role: 'assistant', content: 'c', createdAt: 3, state: 'complete' }
+    ]
+    const view = render(<ChatTimeline {...props} messages={messages} />)
+    const articles = view.container.querySelectorAll('article.message')
+    expect([...articles].map(article => article.querySelector('.message__meta strong')?.textContent))
+      .toEqual(['GoodBuddy', 'GoodBuddy', 'GoodBuddy'])
+    expect([...articles].map(article => article.querySelector('.message__role')?.textContent ?? null))
+      .toEqual(['代码审查专家', '专家团队（并行）', null])
+  })
+
   it('captures only nonempty settled assistant replies, including incomplete replies', () => {
     const onAddToNote = vi.fn()
     const messages: Message[] = [

src/renderer/src/ChatTimeline.tsx

@@ -73,6 +73,7 @@ export type Message = {
   contextCompressions?: ConversationMessage['contextCompressions']
   tools?: ToolActivity[]
   subagents?: SubagentActivity[]
+  expert?: ConversationMessage['expert']
   approval?: {
     id: string
     taskId?: string
@@ -754,6 +755,14 @@ function ChatMessageRowView({
               : t('chat.status.waitingForProgress'))
     : message.status
 
+  const roleCaption = message.role !== 'assistant'
+    ? undefined
+    : message.expert?.kind === 'expert'
+      ? message.expert.name
+      : message.expert?.kind === 'team'
+        ? t('composer.experts.team')
+        : undefined
+
   return (
     <>
     <article
@@ -768,7 +777,7 @@ function ChatMessageRowView({
           <UserRound size={18} />
         )}
       </div>
-      <div className="message__header">
+      <div className={`message__header${roleCaption ? ' message__header--with-role' : ''}`}>
         <div className="message__meta">
           <strong>
             {message.role === 'assistant' ? 'GoodBuddy' : t('chat.user')}
@@ -786,6 +795,11 @@ function ChatMessageRowView({
           )}
           <span>{formatTime(message.createdAt, locale)}</span>
         </div>
+        {roleCaption && (
+          <small className="message__role" title={t('composer.expertLabel')}>
+            {roleCaption}
+          </small>
+        )}
       </div>
       <div className="message__body">
         {message.attachments && message.attachments.length > 0 && (

src/renderer/src/Composer.tsx

@@ -653,6 +653,22 @@ export const Composer = memo(function Composer({
           </div>
         )}
         <div className="composer__input">
+          <div className="composer__input-header">
+            <ComposerMenuSelect
+              ariaLabel={t("composer.expertLabel")}
+              className="composer-picker--expert composer-picker--chip"
+              disabled={
+                isRunning ||
+                runtime?.capability === "image-generation"
+              }
+              icon={<Bot aria-hidden="true" size={13} />}
+              menuOpen={composerMenuOpen === "expert"}
+              onChange={actions.selectExpert}
+              onOpenChange={setExpertMenuOpen}
+              options={assistantExpertOptions}
+              value={selectedExpertId}
+            />
+          </div>
           <ComposerDraftText
             conversationId={conversationId}
             store={composerDrafts}
@@ -1024,20 +1040,6 @@ export const Composer = memo(function Composer({
                   </div>
                 </>
               )}
-              <ComposerMenuSelect
-                ariaLabel={t("composer.expertLabel")}
-                className="composer-picker--expert"
-                disabled={
-                  isRunning ||
-                  runtime?.capability === "image-generation"
-                }
-                icon={<Bot aria-hidden="true" size={15} />}
-                menuOpen={composerMenuOpen === "expert"}
-                onChange={actions.selectExpert}
-                onOpenChange={setExpertMenuOpen}
-                options={assistantExpertOptions}
-                value={selectedExpertId}
-              />
               <div className="runtime-picker">
                 <button
                   aria-expanded={runtimeMenuOpen}

src/renderer/src/conversation-persistence.ts

@@ -41,6 +41,7 @@ export function toConversationMessage(message: Message): ConversationMessage {
     contextCompressions: message.contextCompressions,
     tools: message.tools,
     subagents: message.subagents,
+    expert: message.expert,
     sources: message.sources,
     sourceReferences: message.sourceReferences,
     knowledgeRetrieval: message.knowledgeRetrieval,
@@ -64,6 +65,7 @@ export function toLocalConversationHeader(
     knowledgeLibraryIds: conversation.knowledgeLibraryIds,
     knowledgeRetrievalMode: conversation.knowledgeRetrievalMode,
     storyGraphEnabled: conversation.storyGraphEnabled,
+    selectedExpertId: conversation.selectedExpertId,
     contextMetrics: conversation.contextMetrics,
     contextCompressionState: conversation.contextCompressionState,
     ...(conversation.branch ? { branch: conversation.branch } : {}),

src/renderer/src/conversation-selectors.ts

@@ -151,7 +151,7 @@ export function useConversationActivitySummary(
 export type ActiveConversationView = Pick<
   Conversation,
   | "id" | "title" | "projectId" | "runtimeSelection" | "knowledgeLibraryIds"
-  | "knowledgeRetrievalMode" | "remote" | "branch" | "contextMetrics" | "contextCompressionState"
+  | "knowledgeRetrievalMode" | "selectedExpertId" | "remote" | "branch" | "contextMetrics" | "contextCompressionState"
 > & {
   /** Untouched greeting-only conversation: shown with the default title. */
   unused: boolean;
@@ -188,6 +188,7 @@ export function selectActiveConversationView(
     runtimeSelection: conversation.runtimeSelection,
     knowledgeLibraryIds: conversation.knowledgeLibraryIds,
     knowledgeRetrievalMode: conversation.knowledgeRetrievalMode,
+    selectedExpertId: conversation.selectedExpertId,
     remote: conversation.remote,
     branch: conversation.branch,
     contextMetrics: conversation.contextMetrics,
@@ -214,6 +215,7 @@ export function sameActiveConversationView(
   return left.id === right.id && left.title === right.title &&
     left.projectId === right.projectId &&
     left.knowledgeRetrievalMode === right.knowledgeRetrievalMode &&
+    left.selectedExpertId === right.selectedExpertId &&
     left.unused === right.unused && left.historyLoaded === right.historyLoaded &&
     left.running === right.running && left.messageCount === right.messageCount &&
     sameArrayItems(left.knowledgeLibraryIds ?? [], right.knowledgeLibraryIds ?? []) &&

src/renderer/src/styles.css

@@ -6695,6 +6695,23 @@ button > svg {
   gap: 12px;
 }
 
+.message__header--with-role {
+  flex-direction: column;
+  align-items: flex-start;
+  justify-content: center;
+  gap: 0;
+}
+
+.message__role {
+  max-width: 100%;
+  overflow: hidden;
+  color: var(--text-muted);
+  font-size: var(--font-caption);
+  line-height: 1.3;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 .message--user .message__header {
   width: min(78%, 720px);
   align-self: flex-end;
@@ -8401,7 +8418,7 @@ button > svg {
 .composer__input textarea {
   display: block;
   width: 100%;
-  min-height: 72px;
+  min-height: 56px;
   max-height: 220px;
   padding: 0;
   border: 0;
@@ -8697,6 +8714,42 @@ button > svg {
   width: 148px;
 }
 
+/* Role chip in the top-left corner of the input area. */
+.composer__input-header {
+  display: flex;
+  min-width: 0;
+  align-items: center;
+  margin: calc(var(--space-2) * -1) 0 var(--space-2) calc(var(--space-2) * -1);
+}
+
+.composer-picker--chip > .model-button {
+  width: auto;
+  max-width: 220px;
+  height: 24px;
+  padding: 0 var(--space-2);
+  border-color: transparent;
+  border-radius: 999px;
+  background: var(--surface-subtle);
+  color: var(--text-secondary);
+  font-size: var(--font-caption);
+  font-weight: 500;
+}
+
+.composer-picker--chip > .model-button[aria-expanded="true"] {
+  border-color: var(--accent-selected);
+  background: var(--accent-subtle);
+  color: var(--accent);
+}
+
+.composer-picker--chip > .model-button:disabled {
+  border-color: transparent;
+  background: transparent;
+}
+
+.composer-picker--chip .model-button__label {
+  flex: 0 1 auto;
+}
+
 
 .composer-picker--runtime > .model-button,
 .composer-picker--runtime-action > .model-button {

src/shared/assistant-contracts.ts

@@ -519,6 +519,21 @@ export type ConversationAnsweredQuestion = z.infer<
   typeof conversationAnsweredQuestionSchema
 >
 
+export const conversationMessageExpertSchema = z.union([
+  z
+    .object({
+      kind: z.literal('expert'),
+      id: assistantIdSchema,
+      name: z.string().trim().min(1).max(80)
+    })
+    .strict(),
+  z.object({ kind: z.literal('team') }).strict()
+])
+
+export type ConversationMessageExpert = z.infer<
+  typeof conversationMessageExpertSchema
+>
+
 export const conversationMessageSchema = z
   .object({
     id: assistantIdSchema,
@@ -541,6 +556,11 @@ export const conversationMessageSchema = z
       .optional(),
     tools: z.array(conversationToolActivitySchema).optional(),
     subagents: z.array(conversationSubagentActivitySchema).optional(),
+    /**
+     * Snapshot of the role selected when the reply was requested, so later
+     * renames or deletions do not rewrite history.
+     */
+    expert: conversationMessageExpertSchema.optional(),
     sources: z.array(z.string().max(8_192)).max(100).optional(),
     sourceReferences: z
       .array(
@@ -720,6 +740,8 @@ export const conversationSnapshotSchema = z
     knowledgeLibraryIds: z.array(assistantIdSchema).max(20).optional(),
     knowledgeRetrievalMode: z.enum(['auto', 'always']).optional(),
     storyGraphEnabled: z.boolean().optional(),
+    /** Role picked in the composer for this conversation; absent means the general assistant. */
+    selectedExpertId: z.union([assistantIdSchema, z.literal('team')]).optional(),
     contextMetrics: conversationContextMetricsSchema.optional(),
     contextCompressionState:
       conversationContextCompressionStateSchema.optional(),