feat(desktop): AskUserQuestion inline UI (was a dead no-op) (#101)

The desktop never wired the agent's askUser callback, so any AskUserQuestion
tool call hung forever (agent.answer was a no-op). Wire it end-to-end, mirroring
the existing approval round-trip:
- mac-agent: pass an askUser callback into runAgent (new onAskUser arg).
- window-shim: emit an `ask_user` event with a requestId + question/options,
  stash the resolver, and resolve it in a now-real agent.answer({requestId,answer}).
- Repl: render an inline question card with a button per option (disables the
  composer until answered), records the choice as a system breadcrumb.

Typecheck + lint + format clean; verified live via tauri dev HMR. (UI — still
worth an eyeball when an AskUserQuestion actually fires.)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: oratis

apps/desktop/src/lib/mac-agent.ts

@@ -112,6 +112,13 @@ export interface StartTurnArgs {
    *   'always' — permit + persist a permissions.allow matcher
    */
   onApproval?: (toolName: string, reason: string) => Promise<'allow' | 'deny' | 'always'>;
+  /** Called when the agent's AskUserQuestion tool needs an answer. Resolves to
+   *  the chosen option label (or free text). */
+  onAskUser?: (req: {
+    question: string;
+    options: Array<{ label: string; description: string }>;
+    multiSelect?: boolean;
+  }) => Promise<string>;
 }
 
 export interface StartTurnResult {
@@ -184,6 +191,7 @@ export async function startAgentTurn(args: StartTurnArgs): Promise<StartTurnResu
               return decision === 'allow';
             }
           : undefined,
+        askUser: args.onAskUser ? async (req) => args.onAskUser!(req) : undefined,
         onEvent: args.onEvent,
         // No hook dispatcher, no sessions persistence, no autoCompact in v1 Mac MVP.
       });

apps/desktop/src/lib/window-shim.ts

@@ -36,6 +36,9 @@ function emitEvent(e: unknown): void {
 // resolver here. The UI calls api.agent.approve({ requestId, decision })
 // which pops the resolver and resolves the original promise.
 const pendingApprovals = new Map<string, (decision: 'allow' | 'deny' | 'always') => void>();
+// AskUserQuestion round-trips: same pattern — emit an `ask_user` event, stash
+// the resolver, resolve it when the UI calls api.agent.answer({ requestId, answer }).
+const pendingQuestions = new Map<string, (answer: string) => void>();
 
 function nextRequestId(): string {
   return `req-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 6)}`;
@@ -138,6 +141,21 @@ export function installTauriShim(): void {
               });
             });
           },
+          onAskUser: (req) => {
+            const requestId = nextRequestId();
+            return new Promise<string>((resolve) => {
+              pendingQuestions.set(requestId, resolve);
+              emitEvent({
+                kind: 'event',
+                turnId: pendingTurnId,
+                type: 'ask_user',
+                requestId,
+                question: req.question,
+                options: req.options,
+                multiSelect: req.multiSelect,
+              });
+            });
+          },
         });
         pendingTurnId = result.turnId;
         return result;
@@ -156,10 +174,11 @@ export function installTauriShim(): void {
         pendingApprovals.delete(requestId);
         resolver(decision);
       },
-      async answer() {
-        // AskUserQuestion answers: same — for v1 Mac MVP we don't wire
-        // the inline askUser callback because the renderer doesn't yet
-        // surface that UI.
+      async answer({ requestId, answer }) {
+        const resolver = pendingQuestions.get(requestId);
+        if (!resolver) return; // stale / already answered
+        pendingQuestions.delete(requestId);
+        resolver(answer);
       },
       onEvent(cb: (e: unknown) => void): () => void {
         listeners.push(cb);

apps/desktop/src/screens/Repl.tsx

@@ -179,6 +179,10 @@ interface AgentEvt {
   requestId?: string;
   toolName?: string;
   reason?: string;
+  // ask_user fields (AskUserQuestion tool)
+  question?: string;
+  options?: Array<{ label: string; description: string }>;
+  multiSelect?: boolean;
   // tool_use carries id; we use it on tool_result to attach output to the right card
   id?: string;
 }
@@ -189,6 +193,13 @@ interface PendingApproval {
   reason: string;
 }
 
+interface PendingQuestion {
+  requestId: string;
+  question: string;
+  options: Array<{ label: string; description: string }>;
+  multiSelect?: boolean;
+}
+
 // ─── Component ────────────────────────────────────────────────────────
 
 export function ReplScreen({
@@ -217,6 +228,7 @@ export function ReplScreen({
   const [busy, setBusy] = useState(false);
   const [activeTurnId, setActiveTurnId] = useState<string | null>(null);
   const [pendingApproval, setPendingApproval] = useState<PendingApproval | null>(null);
+  const [pendingQuestion, setPendingQuestion] = useState<PendingQuestion | null>(null);
   // 'high' (6k output) by default — 'medium' (3k) truncates multi-file writes.
   // Overridden by a persisted effortLevel in settings on mount.
   const [effort, setEffort] = useState<Effort>('high');
@@ -279,6 +291,8 @@ export function ReplScreen({
       if (e.kind === 'turn_done') {
         setBusy(false);
         setActiveTurnId(null);
+        setPendingApproval(null);
+        setPendingQuestion(null);
         setMessages((m) => finalizeStreaming(m));
         onTurnComplete?.();
         return;
@@ -351,6 +365,16 @@ export function ReplScreen({
             });
           }
           break;
+        case 'ask_user':
+          if (e.requestId && e.question) {
+            setPendingQuestion({
+              requestId: e.requestId,
+              question: e.question,
+              options: e.options ?? [],
+              multiSelect: e.multiSelect,
+            });
+          }
+          break;
       }
     });
     return () => off();
@@ -491,11 +515,20 @@ export function ReplScreen({
     await window.deepcode.agent.approve({ requestId: req.requestId, decision });
   }
 
+  // ── AskUserQuestion answer ──
+  async function handleAnswer(answer: string): Promise<void> {
+    if (!pendingQuestion) return;
+    const req = pendingQuestion;
+    setPendingQuestion(null);
+    setMessages((m) => [...m, { role: 'system', text: `❯ ${req.question} → ${answer}` }]);
+    await window.deepcode.agent.answer({ requestId: req.requestId, answer });
+  }
+
   // ── Send ──
   async function handleSubmit(e: React.FormEvent): Promise<void> {
     e.preventDefault();
     const text = input.trim();
-    if (!text || busy || pendingApproval) return;
+    if (!text || busy || pendingApproval || pendingQuestion) return;
     setInput('');
     setMessages((m) => [...m, { role: 'user', text }]);
     setBusy(true);
@@ -530,7 +563,7 @@ export function ReplScreen({
   // Lock all the toolbar controls (mode / model / effort) once a turn
   // is in flight or pending approval — changing them mid-turn would
   // contradict the system prompt already sent.
-  const controlsLocked = busy || pendingApproval !== null;
+  const controlsLocked = busy || pendingApproval !== null || pendingQuestion !== null;
 
   // Only the last assistant turn is "active" — its cursor blinks while the rest
   // stay static. Guards against a second cursor if a turn was left streaming.
@@ -577,7 +610,7 @@ export function ReplScreen({
           renderMessage(m, i, pendingApproval, handleApproval, i === activeAssistantIdx),
         )}
 
-        {busy && !pendingApproval && (
+        {busy && !pendingApproval && !pendingQuestion && (
           <div className="msg assistant">
             <div className="avatar">DC</div>
             <div className="body">
@@ -588,6 +621,31 @@ export function ReplScreen({
             </div>
           </div>
         )}
+
+        {pendingQuestion && (
+          <div className="msg assistant">
+            <div className="avatar">DC</div>
+            <div className="body">
+              <div className="author">DeepCode · needs your input</div>
+              <div className="content">
+                <div style={{ marginBottom: 8 }}>{pendingQuestion.question}</div>
+                <div className="approval-row" style={{ flexWrap: 'wrap' }}>
+                  {pendingQuestion.options.map((o) => (
+                    <button
+                      key={o.label}
+                      type="button"
+                      className="btn btn-secondary"
+                      title={o.description}
+                      onClick={() => void handleAnswer(o.label)}
+                    >
+                      {o.label}
+                    </button>
+                  ))}
+                </div>
+              </div>
+            </div>
+          </div>
+        )}
       </div>
 
       <div className="composer">
@@ -599,13 +657,15 @@ export function ReplScreen({
               onChange={(e) => setInput(e.target.value)}
               onKeyDown={handleKeyDown}
               placeholder={
-                pendingApproval
-                  ? 'Approve or reject the tool call above to continue…'
-                  : busy
-                    ? 'Agent is responding…'
-                    : '问点什么…   @ 引用文件   ·   / 命令   ·   # 写入 DEEPCODE.md'
+                pendingQuestion
+                  ? 'Pick an option above to continue…'
+                  : pendingApproval
+                    ? 'Approve or reject the tool call above to continue…'
+                    : busy
+                      ? 'Agent is responding…'
+                      : '问点什么…   @ 引用文件   ·   / 命令   ·   # 写入 DEEPCODE.md'
               }
-              disabled={busy || pendingApproval !== null}
+              disabled={busy || pendingApproval !== null || pendingQuestion !== null}
               rows={Math.min(6, Math.max(1, input.split('\n').length))}
             />
             <div className="toolbar">

apps/desktop/src/types/global.d.ts

@@ -79,7 +79,8 @@ export interface DeepCodeAPI {
     /** Resolve an in-flight permission_request event. `decision === 'always'`
      *  also persists a matcher to ~/.deepcode/settings.json. */
     approve: (args: { requestId: string; decision: 'allow' | 'deny' | 'always' }) => Promise<void>;
-    answer: (args: { turnId: string; questionId: string; answer: string }) => Promise<void>;
+    /** Resolve an in-flight ask_user event with the chosen option label / text. */
+    answer: (args: { requestId: string; answer: string }) => Promise<void>;
     onEvent: (cb: (e: unknown) => void) => () => void;
   };
   onUpdateDownloaded: (cb: (info: UpdateInfo) => void) => () => void;