Add composer prompt-history recall (Up/Down arrows)

Recall previously-sent prompts in the chat composer, shell-style:
- Up in an empty (or already-recalling) composer walks history newest->oldest
- Down walks newer again and restores the original draft past the newest entry
- edit / submit / session-switch exit recall mode; drafts keep normal caret nav

Sent prompts are persisted globally in localStorage (craft-prompt-history),
trimmed, immediate-duplicate-collapsed, capped at 100. The navigation model is a
pure, unit-tested module (prompt-history.ts). No new i18n keys.

Adds a data-testid on the composer input and a CDP assertion driving Up/Down in
the draft state.

Closes #52

Author: claude

apps/electron/src/renderer/components/app-shell/input/FreeFormInput.tsx

@@ -107,6 +107,13 @@ import {
   addRecentWorkingDir,
   removeRecentWorkingDir,
 } from './working-directory-history';
+import {
+  getPromptHistory,
+  recordPrompt,
+  prevPromptIndex,
+  nextPromptIndex,
+  promptAt,
+} from './prompt-history';
 import { CompactPermissionModeSelector } from './CompactPermissionModeSelector';
 import { FEATURE_FLAGS } from '@craft-agent/shared/feature-flags';
 import { inferFileAttachmentMetadata } from './file-attachment-metadata';
@@ -944,6 +951,33 @@ export function FreeFormInput({
   const internalInputRef = React.useRef<RichTextInputHandle>(null);
   const richInputRef = externalInputRef || internalInputRef;
 
+  // Prompt history recall (Up/Down arrows walk previously-sent prompts, shell-style).
+  // `promptHistoryIndexRef` is null when not recalling, otherwise the index into
+  // `promptHistoryRef` currently shown in the composer; `draftBeforeHistoryRef`
+  // holds the draft the user started from so Down can restore it.
+  const promptHistoryRef = React.useRef<string[]>([]);
+  const promptHistoryIndexRef = React.useRef<number | null>(null);
+  const draftBeforeHistoryRef = React.useRef<string>('');
+
+  // Replace the composer contents programmatically (used by history recall):
+  // drive the controlled `value` prop and place the caret at the end.
+  const applyRecalledPrompt = React.useCallback(
+    (text: string) => {
+      setInput(text);
+      syncToParent(text);
+      requestAnimationFrame(() => {
+        richInputRef.current?.setSelectionRange(text.length, text.length);
+      });
+    },
+    [syncToParent, richInputRef],
+  );
+
+  // Reset prompt-history recall when switching sessions.
+  React.useEffect(() => {
+    promptHistoryIndexRef.current = null;
+    draftBeforeHistoryRef.current = '';
+  }, [sessionId]);
+
   // Track last caret position for focus restoration (e.g., after permission mode popover closes)
   const lastCaretPositionRef = React.useRef<number | null>(null);
 
@@ -1844,6 +1878,10 @@ export function FreeFormInput({
       attachments.length > 0 ? attachments : undefined,
       mentions.skills.length > 0 ? mentions.skills : undefined,
     );
+    // Record the sent prompt for Up/Down recall, and exit any recall mode.
+    promptHistoryRef.current = recordPrompt(input);
+    promptHistoryIndexRef.current = null;
+    draftBeforeHistoryRef.current = '';
     setInput('');
     setAttachments([]);
     // Clear draft immediately (cancel any pending debounced sync)
@@ -1971,6 +2009,55 @@ export function FreeFormInput({
       }
     }
 
+    // Prompt history recall: Up/Down walk previously-sent prompts, shell-style.
+    // Only when no menu is open and no modifier/IME is active. Up engages when the
+    // composer is empty (or already recalling); Down only steps while recalling, so
+    // ordinary caret movement in a draft is untouched.
+    if (
+      (e.key === 'ArrowUp' || e.key === 'ArrowDown') &&
+      !e.metaKey &&
+      !e.ctrlKey &&
+      !e.altKey &&
+      !e.shiftKey &&
+      !e.nativeEvent.isComposing &&
+      !inlineMention.isOpen &&
+      !inlineSlash.isOpen &&
+      !inlineLabel.isOpen
+    ) {
+      const recalling = promptHistoryIndexRef.current !== null;
+      if (e.key === 'ArrowUp') {
+        const currentValue = richInputRef.current?.value ?? '';
+        if (recalling || currentValue.trim() === '') {
+          if (!recalling) {
+            // Refresh history from storage and remember the draft to restore.
+            promptHistoryRef.current = getPromptHistory();
+            draftBeforeHistoryRef.current = currentValue;
+          }
+          const history = promptHistoryRef.current;
+          const nextIndex = prevPromptIndex(history, promptHistoryIndexRef.current);
+          const entry = promptAt(history, nextIndex);
+          if (entry !== null) {
+            e.preventDefault();
+            promptHistoryIndexRef.current = nextIndex;
+            applyRecalledPrompt(entry);
+            return;
+          }
+        }
+      } else if (recalling) {
+        // ArrowDown while recalling: step toward newer, restoring the draft past the end.
+        e.preventDefault();
+        const history = promptHistoryRef.current;
+        const nextIndex = nextPromptIndex(history, promptHistoryIndexRef.current);
+        promptHistoryIndexRef.current = nextIndex;
+        applyRecalledPrompt(
+          nextIndex === null
+            ? draftBeforeHistoryRef.current
+            : promptAt(history, nextIndex) ?? '',
+        );
+        return;
+      }
+    }
+
     if (
       e.key === 'Tab' &&
       e.shiftKey &&
@@ -2042,6 +2129,11 @@ export function FreeFormInput({
       // Get previous input value before updating state
       const prevValue = inputRef.current;
 
+      // A real edit exits prompt-history recall mode. Programmatic recall updates
+      // the controlled `value` prop directly (not via this onChange), so this only
+      // fires for genuine user typing/editing.
+      promptHistoryIndexRef.current = null;
+
       setInput(nextValue);
       syncToParent(nextValue); // Debounced sync to parent for draft persistence
 
@@ -2494,6 +2586,7 @@ export function FreeFormInput({
         {!(compactMode && isProcessing) && (
           <RichTextInput
             ref={richInputRef}
+            data-testid="composer-input"
             value={input}
             onChange={handleInputChange}
             onInput={handleRichInput}

apps/electron/src/renderer/components/app-shell/input/__tests__/prompt-history.test.ts

@@ -0,0 +1,158 @@
+import { describe, it, expect, beforeEach } from 'bun:test'
+import {
+  MAX_PROMPT_HISTORY,
+  pushPromptHistory,
+  prevPromptIndex,
+  nextPromptIndex,
+  promptAt,
+  getPromptHistory,
+  recordPrompt,
+} from '../prompt-history'
+
+describe('prompt-history', () => {
+  describe('pushPromptHistory', () => {
+    it('appends a new prompt to the end (newest last)', () => {
+      expect(pushPromptHistory(['a', 'b'], 'c')).toEqual(['a', 'b', 'c'])
+    })
+
+    it('trims the entry before storing', () => {
+      expect(pushPromptHistory([], '  hello  ')).toEqual(['hello'])
+    })
+
+    it('ignores empty / whitespace-only entries', () => {
+      expect(pushPromptHistory(['a'], '')).toEqual(['a'])
+      expect(pushPromptHistory(['a'], '   ')).toEqual(['a'])
+    })
+
+    it('collapses an immediate repeat of the most recent entry', () => {
+      expect(pushPromptHistory(['a', 'b'], 'b')).toEqual(['a', 'b'])
+      // trimming still applies to the repeat check
+      expect(pushPromptHistory(['a', 'b'], '  b  ')).toEqual(['a', 'b'])
+    })
+
+    it('keeps a non-consecutive repeat (only immediate repeats collapse)', () => {
+      expect(pushPromptHistory(['a', 'b'], 'a')).toEqual(['a', 'b', 'a'])
+    })
+
+    it('caps the list to MAX_PROMPT_HISTORY, dropping the oldest', () => {
+      const existing = Array.from({ length: MAX_PROMPT_HISTORY }, (_, i) => `p-${i}`)
+      const result = pushPromptHistory(existing, 'newest')
+      expect(result.length).toBe(MAX_PROMPT_HISTORY)
+      expect(result[result.length - 1]).toBe('newest')
+      expect(result[0]).toBe('p-1') // 'p-0' was dropped
+      expect(result).not.toContain('p-0')
+    })
+
+    it('does not mutate the input array', () => {
+      const input = ['a', 'b']
+      pushPromptHistory(input, 'c')
+      expect(input).toEqual(['a', 'b'])
+    })
+  })
+
+  describe('prevPromptIndex (Up / older)', () => {
+    const history = ['first', 'second', 'third'] // newest last
+
+    it('starts at the newest entry when not yet recalling', () => {
+      expect(prevPromptIndex(history, null)).toBe(2)
+    })
+
+    it('steps one entry older on each subsequent Up', () => {
+      expect(prevPromptIndex(history, 2)).toBe(1)
+      expect(prevPromptIndex(history, 1)).toBe(0)
+    })
+
+    it('clamps at the oldest entry', () => {
+      expect(prevPromptIndex(history, 0)).toBe(0)
+    })
+
+    it('returns null when there is no history', () => {
+      expect(prevPromptIndex([], null)).toBeNull()
+    })
+  })
+
+  describe('nextPromptIndex (Down / newer)', () => {
+    const history = ['first', 'second', 'third']
+
+    it('does nothing when not recalling', () => {
+      expect(nextPromptIndex(history, null)).toBeNull()
+    })
+
+    it('steps one entry newer', () => {
+      expect(nextPromptIndex(history, 0)).toBe(1)
+      expect(nextPromptIndex(history, 1)).toBe(2)
+    })
+
+    it('returns null (exit recall / restore draft) past the newest entry', () => {
+      expect(nextPromptIndex(history, 2)).toBeNull()
+    })
+  })
+
+  describe('promptAt', () => {
+    const history = ['first', 'second', 'third']
+
+    it('returns the entry at a valid index', () => {
+      expect(promptAt(history, 0)).toBe('first')
+      expect(promptAt(history, 2)).toBe('third')
+    })
+
+    it('returns null when not recalling or out of range', () => {
+      expect(promptAt(history, null)).toBeNull()
+      expect(promptAt(history, -1)).toBeNull()
+      expect(promptAt(history, 3)).toBeNull()
+    })
+  })
+
+  describe('Up/Down round trip', () => {
+    it('walks back with Up and forward with Down, restoring the draft', () => {
+      const history = ['one', 'two', 'three']
+      // Up, Up, Up
+      let idx = prevPromptIndex(history, null)
+      expect(promptAt(history, idx)).toBe('three')
+      idx = prevPromptIndex(history, idx)
+      expect(promptAt(history, idx)).toBe('two')
+      idx = prevPromptIndex(history, idx)
+      expect(promptAt(history, idx)).toBe('one')
+      // Down, Down back to newest
+      idx = nextPromptIndex(history, idx)
+      expect(promptAt(history, idx)).toBe('two')
+      idx = nextPromptIndex(history, idx)
+      expect(promptAt(history, idx)).toBe('three')
+      // One more Down exits recall (restore the original draft)
+      idx = nextPromptIndex(history, idx)
+      expect(idx).toBeNull()
+      expect(promptAt(history, idx)).toBeNull()
+    })
+  })
+
+  describe('persistence (getPromptHistory / recordPrompt)', () => {
+    beforeEach(() => {
+      const store = new Map<string, string>()
+      // Minimal localStorage stub so the storage helper can round-trip in bun.
+      ;(globalThis as { localStorage?: unknown }).localStorage = {
+        getItem: (k: string) => (store.has(k) ? store.get(k)! : null),
+        setItem: (k: string, v: string) => void store.set(k, v),
+        removeItem: (k: string) => void store.delete(k),
+        clear: () => store.clear(),
+        key: () => null,
+        length: 0,
+      }
+    })
+
+    it('returns an empty list when nothing has been recorded', () => {
+      expect(getPromptHistory()).toEqual([])
+    })
+
+    it('records prompts and reads them back (newest last)', () => {
+      recordPrompt('hello')
+      recordPrompt('world')
+      expect(getPromptHistory()).toEqual(['hello', 'world'])
+    })
+
+    it('applies push semantics (trim + immediate-repeat collapse) when recording', () => {
+      recordPrompt('  a  ')
+      recordPrompt('a')
+      expect(getPromptHistory()).toEqual(['a'])
+    })
+  })
+})

apps/electron/src/renderer/components/app-shell/input/prompt-history.ts

@@ -0,0 +1,98 @@
+import * as storage from '@/lib/local-storage'
+
+/**
+ * Prompt history for the chat composer.
+ *
+ * Mirrors the "recall your previous prompt with the Up arrow" affordance that
+ * terminal shells, the Claude Code CLI, and the Codex desktop composer all
+ * provide: pressing Up in an empty (or already-recalling) composer walks
+ * backwards through the prompts you have sent, and Down walks forward again,
+ * restoring the draft you started from once you page past the newest entry.
+ *
+ * The list is stored newest-**last** (append order) and persisted globally in
+ * the renderer's localStorage, so history survives restarts and is shared
+ * across sessions — the same behaviour as a shell's history file.
+ *
+ * The navigation model is index-based and deliberately pure so it can be unit
+ * tested without a DOM: `null` means "not currently recalling", otherwise the
+ * index points at the entry in `history` currently shown in the composer.
+ */
+
+export const MAX_PROMPT_HISTORY = 100
+
+/**
+ * Append a submitted prompt to the history list.
+ * - Trims the entry; empty/whitespace-only entries are ignored.
+ * - Collapses an immediate repeat (same as the most recent entry) so hammering
+ *   the same prompt doesn't bloat the list.
+ * - Caps the list to {@link MAX_PROMPT_HISTORY}, dropping the oldest entries.
+ *
+ * Returns a new array; the input is never mutated.
+ */
+export function pushPromptHistory(
+  history: string[],
+  entry: string,
+  maxEntries = MAX_PROMPT_HISTORY,
+): string[] {
+  const trimmed = entry.trim()
+  if (!trimmed) return history
+  if (history.length > 0 && history[history.length - 1] === trimmed) {
+    return history
+  }
+  const next = [...history, trimmed]
+  if (next.length > maxEntries) {
+    return next.slice(next.length - maxEntries)
+  }
+  return next
+}
+
+/**
+ * Index of the entry to show when moving **backwards** (older) with Up.
+ * - From "not recalling" (`null`), start at the newest entry.
+ * - Otherwise step one entry older, clamped at the oldest (index 0).
+ * - Returns `null` when there is no history to recall.
+ */
+export function prevPromptIndex(
+  history: string[],
+  index: number | null,
+): number | null {
+  if (history.length === 0) return null
+  if (index === null) return history.length - 1
+  return Math.max(0, index - 1)
+}
+
+/**
+ * Index of the entry to show when moving **forwards** (newer) with Down.
+ * - Only meaningful while recalling (`index` is a number); returns `null`
+ *   otherwise so the caller leaves the composer alone.
+ * - Stepping past the newest entry returns `null`, signalling "exit recall and
+ *   restore the draft the user started from".
+ */
+export function nextPromptIndex(
+  history: string[],
+  index: number | null,
+): number | null {
+  if (index === null) return null
+  const next = index + 1
+  if (next >= history.length) return null
+  return next
+}
+
+/** The entry at a navigation index, or `null` when not recalling / out of range. */
+export function promptAt(history: string[], index: number | null): string | null {
+  if (index === null || index < 0 || index >= history.length) return null
+  return history[index]
+}
+
+/** Read the persisted prompt history (newest last). */
+export function getPromptHistory(): string[] {
+  const value = storage.get<string[]>(storage.KEYS.promptHistory, [])
+  return Array.isArray(value) ? value.filter((v): v is string => typeof v === 'string') : []
+}
+
+/** Persist a submitted prompt, returning the updated (persisted) list. */
+export function recordPrompt(entry: string): string[] {
+  const next = pushPromptHistory(getPromptHistory(), entry)
+  storage.set(storage.KEYS.promptHistory, next)
+  return next
+}