any key after a recall ends it, and Left is the one that proves the point

A recalled prompt you have started moving around in is a prompt you have adopted, so the next Up must not
walk further back over it — the same fault as recalling over a fresh draft, arrived at from the other side.

Left and Right are why this cannot be inferred from the text. They change nothing, so any rule watching for
edits would miss them entirely, and arrowing into the middle of a recalled prompt is the clearest statement
of intent available: you are working on this one now.

So the composer leaves the history on any keystroke that is not Up or Down. Bare modifiers are excluded —
holding Shift to capitalise the next letter is not editing, and treating it as such would end a recall
between two presses of Up. `Dead` is in that set too: a pending accent on a composing layout is not a
finished keystroke.

leave() clears the stashed draft as well as the position. That draft belonged to the composing session being
left, and handing it back after you have started editing something else would paste an older draft over a
newer one.

Six tests, three of them on the interaction between this and the emptiness rule from the commit before —
together they are what stops Up from eating an edited prompt.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/workspaces/officerdev/src/apps/Chat/EmbeddableChat/useEmbeddableChat.ts

@@ -51,6 +51,15 @@ type UseEmbeddableChatParams = {
   contextId?: string;
 };
 
+/**
+ * Keys that are held rather than typed.
+ *
+ * A modifier press is not editing, and ending a recall on one would break the ordinary act of holding Shift
+ * between two presses of Up. `Dead` is a pending accent on layouts that compose — also not a keystroke you
+ * have finished making.
+ */
+const MODIFIER_KEYS = new Set(['Shift', 'Control', 'Alt', 'Meta', 'CapsLock', 'Dead']);
+
 export function useEmbeddableChat(params: UseEmbeddableChatParams, onMessageComplete?: () => void) {
   const { initialMessage, defaultInput = '', promptPrefix, cwd, autoSend = false, chat: externalChat } = params;
 
@@ -440,6 +449,18 @@ export function useEmbeddableChat(params: UseEmbeddableChatParams, onMessageComp
     }
     if (ev.key === 'ArrowUp') return recallPrompt(ev, -1);
     if (ev.key === 'ArrowDown') return recallPrompt(ev, 1);
+    /*
+      Anything else ends the recall, and Left/Right are the ones that matter.
+
+      A recalled prompt you have started moving around in is a prompt you have adopted — so the next Up must
+      not walk further back over it, for the same reason Up does not overwrite a fresh draft. Arrowing left
+      into the middle of it is the clearest signal of intent there is, and it types nothing, so a rule based
+      on the text changing would miss it entirely.
+
+      Bare modifiers are excluded: holding Shift to capitalise the next letter is not editing, and treating
+      it as such would end the recall between two presses of Up.
+    */
+    if (!MODIFIER_KEYS.has(ev.key)) history.leave();
     if (ev.key === 'Enter' && !ev.shiftKey) {
       ev.preventDefault();
       // Enter on an EMPTY composer with something queued means "don't wait — say it now". The keystroke

src/workspaces/officerdev/src/apps/Chat/EmbeddableChat/usePromptHistory.test.tsx

@@ -103,3 +103,44 @@ describe('what gets remembered', () => {
     expect(current.step(-1, '')).toBe('three');
   });
 });
+
+describe('leaving the history', () => {
+  // The rule this exists for: a recalled prompt you have started editing — or merely arrowed into — is
+  // yours now, and the next Up must not walk further back over it.
+  test('a keystroke after a recall ends it, so Up no longer walks', () => {
+    const { current } = mount();
+    current.record('one');
+    current.record('two');
+
+    expect(current.step(-1, '')).toBe('two');
+    expect(current.isRecalling()).toBe(true);
+
+    current.leave();
+    expect(current.isRecalling()).toBe(false);
+  });
+
+  // The composer's guard is "empty, or recalling". Once we have left, a non-empty box is a draft — so the
+  // two halves together are what stop Up from eating an edited prompt.
+  test('after leaving, the recalled text is treated as a draft', () => {
+    const { current } = mount();
+    current.record('one');
+    current.step(-1, '');
+    current.leave();
+
+    const mayRecall = (value: string) => value.trim() === '' || current.isRecalling();
+    expect(mayRecall('one, edited')).toBe(false);
+    expect(mayRecall('')).toBe(true);
+  });
+
+  // The stashed draft goes with it. Handing an older draft back after you have started editing something
+  // else would paste the wrong text over the right one.
+  test('the stashed draft does not come back later', () => {
+    const { current } = mount();
+    current.record('sent');
+    expect(current.step(-1, 'a draft')).toBe('sent');
+    current.leave();
+    // Entering again stashes what is there NOW, and Down returns that rather than the abandoned draft.
+    expect(current.step(-1, 'something else')).toBe('sent');
+    expect(current.step(1, 'sent')).toBe('something else');
+  });
+});

src/workspaces/officerdev/src/apps/Chat/EmbeddableChat/usePromptHistory.ts

@@ -34,6 +34,17 @@ export type PromptHistory = {
    * then refuse. This is the difference between "there is text" and "there is text of yours".
    */
   isRecalling: () => boolean;
+  /**
+   * Stop being in the history — the recalled text is now the person's own draft.
+   *
+   * Called on any keystroke that is not Up or Down. The moment you edit a recalled prompt, or even just
+   * move the caret through it with Left, you have adopted it: pressing Up after that would throw away
+   * something you were working on, which is the same fault as recalling over a fresh draft.
+   *
+   * The stashed draft goes too. It belonged to the composing session this leaves, and handing it back after
+   * you have started editing something else would paste an older draft over a newer one.
+   */
+  leave: () => void;
 };
 
 export function usePromptHistory(): PromptHistory {
@@ -98,5 +109,10 @@ export function usePromptHistory(): PromptHistory {
 
   const isRecalling = useCallback(() => indexRef.current !== null, []);
 
-  return { record, step, isRecalling };
+  const leave = useCallback(() => {
+    indexRef.current = null;
+    draftRef.current = '';
+  }, []);
+
+  return { record, step, isRecalling, leave };
 }