fix(cli): clear promptSuggestion on submit and accept paths

Addresses doudouOUC review on #5145. Since abortPromptSuggestion was
changed to preserve `promptSuggestion` for type-then-delete restore, the
submit and accept paths leaked stale suggestion text:

- handleSubmitAndClear only called followup.dismiss(); after a synchronous
  command (/clear, /help) that never triggers AppContainer's streaming
  transition, the placeholder kept showing the old suggestion.
- Tab/Right/Enter accept never cleared the prop, so clearing the buffer
  without submitting (Ctrl+U) made the accepted suggestion reappear as a
  ghost placeholder.

Both now call onPromptSuggestionDismiss?.() after the followup action. Also
reuse the availableSuggestion single-source-of-truth in hasTabConsumer
instead of an inlined parallel expression, and add useFollowupSuggestions
tests asserting the accept_source guard suppresses time_to_first_keystroke_ms
on fallback accepts.

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

packages/cli/src/ui/components/InputPrompt.tsx

@@ -395,8 +395,13 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
       // entry rather than advancing from whatever index the user picked.
       resetHistoryNavRef.current();
 
-      // Dismiss follow-up suggestion after submit
+      // Dismiss follow-up suggestion after submit. `followup.dismiss()` only
+      // resets the controller; `onPromptSuggestionDismiss` also clears the
+      // persisted `promptSuggestion` prop so the placeholder doesn't leak a
+      // stale suggestion after synchronous commands (e.g. /clear, /help) that
+      // never trigger the streaming-transition effect in AppContainer.
       followup.dismiss();
+      onPromptSuggestionDismiss?.();
 
       // Clear attachments after submit
       setAttachments([]);
@@ -418,6 +423,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
       config,
       pendingPastes,
       followup,
+      onPromptSuggestionDismiss,
     ],
   );
 
@@ -1007,6 +1013,10 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
         // suggestion (e.g. after type-then-delete), `fallbackText` carries the
         // still-available placeholder text so telemetry is logged either way.
         followup.accept('tab', { fallbackText: promptSuggestion ?? undefined });
+        // Clear the persisted `promptSuggestion` prop too, otherwise it survives
+        // the accept and reappears as a ghost placeholder once the buffer is
+        // cleared without submitting (e.g. Ctrl+U).
+        onPromptSuggestionDismiss?.();
         return true;
       }
 
@@ -1021,6 +1031,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
         followup.accept('right', {
           fallbackText: promptSuggestion ?? undefined,
         });
+        onPromptSuggestionDismiss?.();
         return true;
       }
 
@@ -1277,6 +1288,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
           followup.accept('enter', {
             fallbackText: promptSuggestion ?? undefined,
           });
+          onPromptSuggestionDismiss?.();
           return true;
         }
         if (buffer.text.trim()) {
@@ -1614,9 +1626,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
   // this drops to false; deleting back to empty restores it.
   const hasTabConsumer =
     shouldShowSuggestions ||
-    (buffer.text.length === 0 &&
-      ((followup.state.isVisible && Boolean(followup.state.suggestion)) ||
-        Boolean(promptSuggestion))) ||
+    (buffer.text.length === 0 && Boolean(availableSuggestion)) ||
     Boolean(completion.midInputGhostText?.acceptText);
 
   // Narrow signal — autocomplete dropdown only. Composer hides Footer /

packages/cli/src/ui/hooks/useFollowupSuggestions.test.tsx

@@ -0,0 +1,104 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { act, renderHook } from '@testing-library/react';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { Config, PromptSuggestionEvent } from '@qwen-code/qwen-code-core';
+
+const { mockLogPromptSuggestion } = vi.hoisted(() => ({
+  mockLogPromptSuggestion: vi.fn(),
+}));
+
+vi.mock('@qwen-code/qwen-code-core', async (importOriginal) => {
+  const actual =
+    await importOriginal<typeof import('@qwen-code/qwen-code-core')>();
+  return {
+    ...actual,
+    logPromptSuggestion: mockLogPromptSuggestion,
+  };
+});
+
+import { useFollowupSuggestionsCLI } from './useFollowupSuggestions.js';
+
+// Mirror of SUGGESTION_DELAY_MS in core's followupState controller.
+const SUGGESTION_DELAY_MS = 300;
+const config = {} as Config;
+
+function acceptedEvent(): PromptSuggestionEvent | undefined {
+  const call = mockLogPromptSuggestion.mock.calls.find(
+    ([, event]) => (event as PromptSuggestionEvent).outcome === 'accepted',
+  );
+  return call?.[1] as PromptSuggestionEvent | undefined;
+}
+
+describe('useFollowupSuggestionsCLI telemetry', () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    mockLogPromptSuggestion.mockReset();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it('omits time_to_first_keystroke_ms on fallback accepts even with stale shown/keystroke refs', () => {
+    const { result } = renderHook(() =>
+      useFollowupSuggestionsCLI({ enabled: true, config }),
+    );
+
+    // Show a live suggestion so prevShownAtRef + firstKeystrokeAtRef get set
+    // from this turn — exactly the stale state that would corrupt a later
+    // fallback accept if the accept_source guard were missing.
+    act(() => {
+      result.current.setSuggestion('run the tests');
+      vi.advanceTimersByTime(SUGGESTION_DELAY_MS);
+    });
+    expect(result.current.state.isVisible).toBe(true);
+
+    act(() => {
+      vi.advanceTimersByTime(50);
+      result.current.recordKeystroke();
+    });
+
+    // Drop the live suggestion and accept via fallback in the same tick, before
+    // the ref-reset effect runs. accept_source is 'fallback' (no live
+    // suggestion), so the keystroke delta must be suppressed.
+    act(() => {
+      result.current.setSuggestion(null);
+      result.current.accept('tab', { fallbackText: 'run the tests' });
+    });
+
+    const event = acceptedEvent();
+    expect(event).toBeDefined();
+    expect(event?.accept_source).toBe('fallback');
+    expect(event?.time_to_first_keystroke_ms).toBeUndefined();
+  });
+
+  it('includes time_to_first_keystroke_ms on live accepts', () => {
+    const { result } = renderHook(() =>
+      useFollowupSuggestionsCLI({ enabled: true, config }),
+    );
+
+    act(() => {
+      result.current.setSuggestion('run the tests');
+      vi.advanceTimersByTime(SUGGESTION_DELAY_MS);
+    });
+
+    act(() => {
+      vi.advanceTimersByTime(50);
+      result.current.recordKeystroke();
+    });
+
+    act(() => {
+      result.current.accept('tab');
+    });
+
+    const event = acceptedEvent();
+    expect(event).toBeDefined();
+    expect(event?.accept_source).toBe('live');
+    expect(event?.time_to_first_keystroke_ms).toBe(50);
+  });
+});