feat(chat): valide le routing cellKind=chat côté frontend et corrige UX

- Ajoute cellKind dans AgentChatHandle et vérifie que launchAgentChat reçoit cellKind:chat
- Rejette avec erreur STRUCTURED_ROUTED_TO_PTY si le backend route vers PTY
- Ajoute cellKind:chat dans MockAgentGateway.launchAgentChat
- Corrige l'overflow du layout CustomAgentChatView (bounded shell avec scroll + composer fixe)
- Dédouble les prompts utilisateur quand le stream les echo
- Ajoute les tests launchAgentChat returns handle only when confirms chat et launchAgentChat rejects PTY-routed launch
- Ajoute les tests does not duplicate user prompt when echoed et keeps chat shell bounded

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/adapters/agent.test.ts

@@ -170,4 +170,77 @@ describe("TauriAgentGateway invoke payloads", () => {
     });
     expect(invoke).not.toHaveBeenCalledWith("close_agent_session", expect.anything());
   });
+
+  it("launchAgentChat returns a handle only when launch_agent confirms cellKind chat", async () => {
+    invoke.mockResolvedValueOnce({
+      sessionId: "chat-session-1",
+      cwd: "/repo",
+      rows: 24,
+      cols: 80,
+      cellKind: "chat",
+      assignedConversationId: "conversation-1",
+    });
+
+    const out = await new TauriAgentGateway().launchAgentChat("proj-1", "agent-2", {
+      cwd: "/repo",
+      rows: 24,
+      cols: 80,
+      conversationId: "conversation-0",
+      nodeId: "node-3",
+    });
+
+    expect(invoke).toHaveBeenCalledWith("launch_agent", {
+      request: {
+        projectId: "proj-1",
+        agentId: "agent-2",
+        rows: 24,
+        cols: 80,
+        cellKind: "chat",
+        conversationId: "conversation-0",
+        nodeId: "node-3",
+      },
+      onOutput: expect.anything(),
+    });
+    expect(out).toEqual({
+      sessionId: "chat-session-1",
+      cellKind: "chat",
+      assignedConversationId: "conversation-1",
+    });
+  });
+
+  it("launchAgentChat rejects a PTY-routed launch before returning a fake structured session", async () => {
+    const log = vi.spyOn(console, "error").mockImplementation(() => {});
+    invoke.mockResolvedValueOnce({
+      sessionId: "pty-session-1",
+      cwd: "/repo",
+      rows: 24,
+      cols: 80,
+      cellKind: "pty",
+    });
+
+    await expect(
+      new TauriAgentGateway().launchAgentChat("proj-1", "agent-2", {
+        cwd: "/repo",
+        rows: 24,
+        cols: 80,
+        nodeId: "node-3",
+      }),
+    ).rejects.toEqual({
+      code: "STRUCTURED_ROUTED_TO_PTY",
+      message:
+        "custom CLI launch for agent agent-2 in project proj-1 returned cellKind=pty; expected chat. sessionId=pty-session-1; nodeId=node-3",
+    });
+    expect(log).toHaveBeenCalledWith(
+      "[ticket149] launchAgentChat:routed-to-non-chat",
+      expect.objectContaining({
+        projectId: "proj-1",
+        agentId: "agent-2",
+        response: expect.objectContaining({
+          sessionId: "pty-session-1",
+          cellKind: "pty",
+        }),
+      }),
+    );
+    log.mockRestore();
+  });
 });

frontend/src/adapters/agent.ts

@@ -18,6 +18,7 @@ import type {
   Agent,
   AgentContextDocument,
   EffortSelection,
+  GatewayError,
   ReplyChunk,
   ResumableAgent,
   TerminalSession,
@@ -42,10 +43,28 @@ interface LaunchAgentResponse {
   cwd: string;
   rows: number;
   cols: number;
+  /** Backend-derived routing: `chat` for structured sessions, `pty` for native TUI. */
+  cellKind?: "chat" | "pty";
   /** Conversation id minted by this launch (omitted when nothing was assigned). */
   assignedConversationId?: string;
 }
 
+function structuredLaunchRoutedToPtyError(
+  projectId: string,
+  agentId: string,
+  options: OpenTerminalOptions,
+  response: LaunchAgentResponse,
+): GatewayError {
+  const actual = response.cellKind ?? "missing";
+  return {
+    code: "STRUCTURED_ROUTED_TO_PTY",
+    message:
+      `custom CLI launch for agent ${agentId} in project ${projectId} ` +
+      `returned cellKind=${actual}; expected chat. ` +
+      `sessionId=${response.sessionId}; nodeId=${options.nodeId ?? "none"}`,
+  };
+}
+
 export class TauriAgentGateway implements AgentGateway {
   listAgents(projectId: string): Promise<Agent[]> {
     return invoke<Agent[]>("list_agents", { projectId });
@@ -194,13 +213,32 @@ export class TauriAgentGateway implements AgentGateway {
         agentId,
         rows: options.rows,
         cols: options.cols,
+        cellKind: "chat",
         conversationId: options.conversationId ?? null,
         nodeId: options.nodeId ?? null,
       },
       onOutput: channel,
     });
+    if (res.cellKind !== "chat") {
+      const error = structuredLaunchRoutedToPtyError(projectId, agentId, options, res);
+      console.error("[ticket149] launchAgentChat:routed-to-non-chat", {
+        projectId,
+        agentId,
+        request: {
+          rows: options.rows,
+          cols: options.cols,
+          cellKind: "chat",
+          conversationId: options.conversationId ?? null,
+          nodeId: options.nodeId ?? null,
+        },
+        response: res,
+        error,
+      });
+      throw error;
+    }
     return {
       sessionId: res.sessionId,
+      cellKind: "chat",
       ...(res.assignedConversationId
         ? { assignedConversationId: res.assignedConversationId }
         : {}),

frontend/src/adapters/mock/index.ts

@@ -801,6 +801,7 @@ export class MockAgentGateway implements AgentGateway {
     }
     return {
       sessionId,
+      cellKind: "chat",
       ...(!options.conversationId
         ? { assignedConversationId: `mock-conversation-${sessionId}` }
         : {}),

frontend/src/features/agents/CustomAgentChatView.test.tsx

@@ -152,6 +152,112 @@ describe("CustomAgentChatView", () => {
     expect(screen.queryByText(/structured session gone/)).toBeNull();
   });
 
+  it("does not duplicate the user prompt when the stream echoes it back", async () => {
+    const agent = {
+      launchAgentChat: vi.fn(),
+      reattachAgentChat: vi.fn(async (sessionId: string) => ({
+        sessionId,
+        scrollback: [],
+      })),
+      sendAgentChat: vi.fn(async (_sessionId: string, _prompt: string, onChunk) => {
+        onChunk({ kind: "userPrompt", text: "hello agent" });
+        onChunk({ kind: "final", content: "done" });
+      }),
+      cancelAgentChat: vi.fn(async () => {}),
+      closeAgentChat: vi.fn(async () => {}),
+    };
+
+    render(
+      <DIProvider
+        gateways={{
+          agent,
+          system: { pickFile: vi.fn(async () => null) },
+        } as unknown as Gateways}
+      >
+        <CustomAgentChatView
+          projectId="project-1"
+          agentId="agent-1"
+          agentName="Worker"
+          profile={profile}
+          cwd="/repo"
+          nodeId="node-1"
+          sessionId="chat-session-1"
+          conversationId="conversation-1"
+          onSessionId={vi.fn()}
+          onConversationId={vi.fn()}
+        />
+      </DIProvider>,
+    );
+
+    await waitFor(() =>
+      expect(agent.reattachAgentChat).toHaveBeenCalledWith(
+        "chat-session-1",
+        expect.any(Function),
+      ),
+    );
+
+    fireEvent.change(screen.getByLabelText(/message CLI custom/), {
+      target: { value: "hello agent" },
+    });
+    fireEvent.click(screen.getByRole("button", { name: "Envoyer" }));
+
+    await screen.findByText("done");
+    expect(screen.getAllByText("hello agent")).toHaveLength(1);
+  });
+
+  it("keeps the chat shell bounded with a scrollable message area and fixed composer", async () => {
+    const agent = {
+      launchAgentChat: vi.fn(() => new Promise<never>(() => {})),
+      reattachAgentChat: vi.fn(),
+      sendAgentChat: vi.fn(() => new Promise<void>(() => {})),
+      cancelAgentChat: vi.fn(async () => {}),
+      closeAgentChat: vi.fn(async () => {}),
+    };
+
+    render(
+      <DIProvider
+        gateways={{
+          agent,
+          system: { pickFile: vi.fn(async () => null) },
+        } as unknown as Gateways}
+      >
+        <CustomAgentChatView
+          projectId="project-1"
+          agentId="agent-1"
+          agentName="Worker with a very long name that must not collide with controls"
+          profile={{
+            ...profile,
+            name: "Structured profile with a very long display name",
+          }}
+          cwd="/repo"
+          nodeId="node-1"
+          sessionId={null}
+          conversationId="conversation-1"
+          onSessionId={vi.fn()}
+          onConversationId={vi.fn()}
+        />
+      </DIProvider>,
+    );
+
+    const shell = screen.getByTestId("custom-agent-chat-view");
+    const toolbar = await screen.findByRole("toolbar", {
+      name: "custom agent chat actions",
+    });
+    const scroll = screen.getByTestId("custom-agent-chat-scroll");
+    const composer = screen.getByTestId("custom-agent-chat-composer");
+    const cancel = await screen.findByRole("button", { name: "Cancel" });
+
+    expect(shell.className).toContain("h-full");
+    expect(shell.className).toContain("min-h-0");
+    expect(shell.className).toContain("overflow-hidden");
+    expect(toolbar.className).toContain("overflow-hidden");
+    expect(cancel.className).toContain("shrink-0");
+    expect(scroll.className).toContain("flex-1");
+    expect(scroll.className).toContain("basis-0");
+    expect(scroll.className).toContain("overflow-y-auto");
+    expect(composer.className).toContain("shrink-0");
+  });
+
   it("falls back when Tauri surfaces structured session NOT_FOUND as a raw string", async () => {
     const agent = {
       launchAgentChat: vi.fn(async () => ({
@@ -476,6 +582,7 @@ describe("CustomAgentChatView", () => {
     const agent = {
       launchAgentChat: vi.fn(async () => ({
         sessionId: "new-session",
+        cellKind: "chat",
         assignedConversationId: "conversation-2",
       })),
       reattachAgentChat: vi.fn().mockRejectedValueOnce({
@@ -514,6 +621,49 @@ describe("CustomAgentChatView", () => {
     );
   });
 
+  it("does not publish a session id when custom launch is refused as PTY-routed", async () => {
+    const agent = {
+      launchAgentChat: vi.fn().mockRejectedValueOnce({
+        code: "STRUCTURED_ROUTED_TO_PTY",
+        message:
+          "custom CLI launch for agent agent-1 in project project-1 returned cellKind=pty; expected chat. sessionId=pty-session-1; nodeId=node-1",
+      }),
+      reattachAgentChat: vi.fn(),
+      sendAgentChat: vi.fn(() => new Promise<void>(() => {})),
+      cancelAgentChat: vi.fn(async () => {}),
+      closeAgentChat: vi.fn(async () => {}),
+    };
+    const onSessionId = vi.fn();
+
+    render(
+      <DIProvider
+        gateways={{
+          agent,
+          system: { pickFile: vi.fn(async () => null) },
+        } as unknown as Gateways}
+      >
+        <CustomAgentChatView
+          projectId="project-1"
+          agentId="agent-1"
+          agentName="Worker"
+          profile={profile}
+          cwd="/repo"
+          nodeId="node-1"
+          sessionId={null}
+          conversationId="conversation-1"
+          onSessionId={onSessionId}
+          onConversationId={vi.fn()}
+        />
+      </DIProvider>,
+    );
+
+    const alert = await screen.findByRole("alert");
+    expect(alert.textContent).toContain("cellKind=pty");
+    expect(agent.launchAgentChat).toHaveBeenCalledTimes(1);
+    expect(agent.reattachAgentChat).not.toHaveBeenCalled();
+    expect(onSessionId).not.toHaveBeenCalled();
+  });
+
   it("recovers when post-launch reattach reports NOT_FOUND", async () => {
     const agent = {
       launchAgentChat: vi

frontend/src/features/agents/CustomAgentChatView.tsx

@@ -93,6 +93,12 @@ function appendAgentDelta(turns: ChatTurn[], text: string): ChatTurn[] {
   return next;
 }
 
+function appendUserPrompt(turns: ChatTurn[], text: string): ChatTurn[] {
+  const last = turns[turns.length - 1];
+  if (last?.role === "user" && last.text === text) return turns;
+  return [...turns, { role: "user", text }];
+}
+
 function foldChunk(turns: ChatTurn[], raw: unknown): ChatTurn[] {
   if (!isReplyRecord(raw)) {
     return [...turns, { role: "unknown", text: unknownChunkLabel(raw) }];
@@ -119,7 +125,7 @@ function foldChunk(turns: ChatTurn[], raw: unknown): ChatTurn[] {
     }
     case "userPrompt":
     case "UserPrompt":
-      return [...turns, { role: "user", text: String(raw.text ?? raw.prompt ?? "") }];
+      return appendUserPrompt(turns, String(raw.text ?? raw.prompt ?? ""));
     default:
       return [...turns, { role: "unknown", text: unknownChunkLabel(raw) }];
   }
@@ -481,20 +487,31 @@ export function CustomAgentChatView({
   return (
     <div
       data-testid="custom-agent-chat-view"
-      className="flex h-full min-h-0 flex-col bg-surface text-content"
+      className="flex h-full min-h-0 flex-col overflow-hidden bg-surface text-content"
     >
-      <div className="flex shrink-0 items-center justify-between gap-2 border-b border-border px-3 py-2">
+      <div
-        <div className="min-w-0">
+        role="toolbar"
+        aria-label="custom agent chat actions"
+        className="flex shrink-0 items-center gap-2 overflow-hidden border-b border-border px-3 py-2"
+      >
+        <div className="min-w-0 flex-1 overflow-hidden">
           <div className="truncate text-sm font-medium">{agentName}</div>
           <div className="truncate text-xs text-muted">
             CLI custom · {profile.name}
           </div>
         </div>
-        {(opening || busy) && (
+        <div className="flex shrink-0 items-center justify-end gap-2">
-          <Button size="sm" variant="danger" onClick={() => void cancel()}>
+          {(opening || busy) && (
-            Cancel
+            <Button
-          </Button>
+              size="sm"
-        )}
+              variant="danger"
+              className="shrink-0 whitespace-nowrap"
+              onClick={() => void cancel()}
+            >
+              Cancel
+            </Button>
+          )}
+        </div>
       </div>
 
       {!supported && (
@@ -508,7 +525,11 @@ export function CustomAgentChatView({
         </p>
       )}
 
-      <div ref={scrollRef} className="flex min-h-0 flex-1 flex-col gap-2 overflow-auto px-3 py-3">
+      <div
+        ref={scrollRef}
+        data-testid="custom-agent-chat-scroll"
+        className="flex min-h-0 flex-1 basis-0 flex-col gap-2 overflow-x-hidden overflow-y-auto px-3 py-3"
+      >
         {opening && turns.length === 0 ? (
           <div className="flex items-center gap-2 text-sm text-muted">
             <Spinner size={14} />
@@ -523,7 +544,10 @@ export function CustomAgentChatView({
         )}
       </div>
 
-      <div className="flex shrink-0 flex-col gap-2 border-t border-border bg-raised/40 p-2">
+      <div
+        data-testid="custom-agent-chat-composer"
+        className="flex shrink-0 flex-col gap-2 border-t border-border bg-raised/40 p-2"
+      >
         {attachment && (
           <div className="flex items-center justify-between gap-2 rounded-md border border-border bg-surface px-2 py-1 text-xs text-muted">
             <span className="truncate">Fichier joint: {attachment}</span>
@@ -532,7 +556,7 @@ export function CustomAgentChatView({
             </button>
           </div>
         )}
-        <div className="flex items-end gap-2">
+        <div className="flex min-w-0 items-end gap-2">
           <textarea
             aria-label={`message CLI custom ${nodeId}`}
             className={cn(
@@ -551,10 +575,22 @@ export function CustomAgentChatView({
               }
             }}
           />
-          <Button size="sm" variant="ghost" disabled={!supported || opening || busy} onClick={() => void pickAttachment()}>
+          <Button
+            size="sm"
+            variant="ghost"
+            className="shrink-0 whitespace-nowrap"
+            disabled={!supported || opening || busy}
+            onClick={() => void pickAttachment()}
+          >
             Joindre
           </Button>
-          <Button size="sm" disabled={!canSend} loading={busy} onClick={() => void send()}>
+          <Button
+            size="sm"
+            className="shrink-0 whitespace-nowrap"
+            disabled={!canSend}
+            loading={busy}
+            onClick={() => void send()}
+          >
             Envoyer
           </Button>
         </div>
@@ -566,8 +602,8 @@ export function CustomAgentChatView({
 function ChatBubble({ turn }: { turn: ChatTurn }) {
   if (turn.role === "tool") {
     return (
-      <div className="flex justify-center">
+      <div className="flex min-w-0 justify-center">
-        <span className="max-w-[80%] rounded-md border border-border bg-raised px-2 py-1 text-xs text-muted">
+        <span className="max-w-[80%] truncate rounded-md border border-border bg-raised px-2 py-1 text-xs text-muted">
           {turn.label}
         </span>
       </div>
@@ -575,8 +611,8 @@ function ChatBubble({ turn }: { turn: ChatTurn }) {
   }
   if (turn.role === "final") {
     return (
-      <div className="flex justify-end">
+      <div className="flex min-w-0 justify-end">
-        <div className="max-w-[86%] rounded-md border border-success/50 bg-success/10 px-3 py-2 text-sm text-content">
+        <div className="min-w-0 max-w-[86%] overflow-hidden rounded-md border border-success/50 bg-success/10 px-3 py-2 text-sm text-content">
           <div className="mb-1 text-xs font-semibold text-success">Task Complete</div>
           <p className="whitespace-pre-wrap break-words">{turn.text}</p>
         </div>
@@ -585,8 +621,8 @@ function ChatBubble({ turn }: { turn: ChatTurn }) {
   }
   if (turn.role === "error" || turn.role === "unknown") {
     return (
-      <div className="flex justify-center">
+      <div className="flex min-w-0 justify-center">
-        <div className="max-w-[86%] rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-xs text-danger">
+        <div className="min-w-0 max-w-[86%] overflow-hidden rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-xs text-danger">
           {turn.role === "unknown" ? "Chunk inconnu reçu: " : ""}
           <span className="whitespace-pre-wrap break-words">{turn.text}</span>
         </div>
@@ -596,10 +632,10 @@ function ChatBubble({ turn }: { turn: ChatTurn }) {
 
   const user = turn.role === "user";
   return (
-    <div className={cn("flex", user ? "justify-start" : "justify-end")}>
+    <div className={cn("flex min-w-0", user ? "justify-start" : "justify-end")}>
       <div
         className={cn(
-          "max-w-[82%] rounded-lg border px-3 py-2 text-sm text-content",
+          "min-w-0 max-w-[82%] overflow-hidden rounded-lg border px-3 py-2 text-sm text-content",
           user ? "border-border bg-raised" : "border-primary/25 bg-primary/10",
         )}
       >

frontend/src/ports/index.ts

@@ -161,6 +161,8 @@ export interface ConversationDetails {
 export interface AgentChatHandle {
   /** Stable structured session id. */
   readonly sessionId: string;
+  /** Backend-confirmed cell routing for this launch. Must be `chat`. */
+  readonly cellKind: "chat";
   /** Conversation id assigned by launch when the backend minted one. */
   readonly assignedConversationId?: string;
 }