A finished turn ends on its changed files (#74732)

* feat(desktop): open the review pane on a given file

toggleReview is a toggle, so it can't back a "take me to the diff" affordance
-- pressing it when the pane is already up hides the thing you asked to see.
revealReview is the open-only half (toggleReview now calls it for its own open
branch), and openReviewForPath goes one further: refresh, then select the file.

A tool reports the path it wrote absolute while git reports repo-relative, so
the two are matched on the tail. fileEditPath is exported for the same reason
-- the caller needs the same path the tool row derives.

* feat(desktop): derive a turn's changed files from its tool parts

A finished turn already carries everything the summary needs: each file-edit
tool part holds the path it touched and the inline diff it produced. Folding
those into one row per file, with repeat edits to a file summed, means the card
costs no extra git probe.

Only landed edits count -- a call still running has no result, and a failed one
changed nothing.

* i18n(desktop): copy for the changed-files card

* feat(desktop): close a turn on its changed-files card

A turn that edited files now ends with a summary panel: one row per file with
its +/-, a Review action opening the diff pane, and a row click opening that
file's diff.

It rides only the newest message. The card describes a working tree, and that
tree has moved on by the next turn -- so rather than leaving a trail of stale
cards down the transcript, sending the next message retires it. While the turn
is still streaming the selector returns a stable empty list, so the tool rows
narrate the edits and the delta stream never re-renders the card.

apps/desktop/src/components/assistant-ui/thread/assistant-message.tsx

@@ -9,6 +9,7 @@ import {
 import { useStore } from '@nanostores/react'
 import { type FC, useCallback, useMemo, useState } from 'react'
 
+import { ChangedFilesCard } from '@/components/assistant-ui/thread/changed-files-card'
 import {
   contentHasVisibleText,
   messageContentText,
@@ -34,6 +35,10 @@ import { playSpeechText, stopVoicePlayback } from '@/lib/voice-playback'
 import { notifyError } from '@/store/notifications'
 import { $voicePlayback } from '@/store/voice-playback'
 
+// Stable empty identity for the settled-parts selector — a fresh [] per render
+// would re-derive the changed-files card on every message re-render.
+const EMPTY_PARTS: readonly unknown[] = []
+
 interface MessageActionProps {
   messageId: string
   /** Lazy accessor — reads the live message text at action time. Passing the
@@ -83,6 +88,21 @@ export const AssistantMessage: FC<{
 
   const getMessageText = useCallback(() => messageContentText(messageRuntime.getState().content), [messageRuntime])
 
+  // Cursor's changed-files card only appears once the turn settles: while the
+  // agent is still editing, the tool rows narrate each patch and a card that
+  // grew a row per write would thrash the transcript. `[]` while running keeps
+  // this selector referentially stable across the 30 Hz delta stream.
+  //
+  // It also only rides the LAST turn. The card is a "here's what just landed"
+  // summary, not a per-turn artifact: leaving one behind on every reply would
+  // stack a wall of stale cards down the transcript. Sending the next message
+  // retires it — the working tree it describes is already history by then.
+  const settledParts = useAuiState(s => {
+    const isLastMessage = s.thread.messages[s.thread.messages.length - 1]?.id === s.message.id
+
+    return s.message.status?.type === 'running' || !isLastMessage ? EMPTY_PARTS : s.message.parts
+  })
+
   const enterRef = useEnterAnimation(isRunning, `assistant-message:${messageId}`)
 
   // Double-click the reply to heart it (iMessage). Undefined while reactions
@@ -134,6 +154,9 @@ export const AssistantMessage: FC<{
       {hasVisibleText && !isInterim && (
         <AssistantFooter getMessageText={getMessageText} messageId={messageId} onBranchInNewChat={onBranchInNewChat} />
       )}
+      {/* Last thing in the turn — under the action bar, the way Cursor ends a
+          turn on its summary rather than burying it above the controls. */}
+      <ChangedFilesCard parts={settledParts} />
     </MessagePrimitive.Root>
   )
 }

apps/desktop/src/components/assistant-ui/thread/changed-files-card.tsx

@@ -0,0 +1,60 @@
+import { type FC, useMemo } from 'react'
+
+import { deriveChangedFiles } from '@/components/assistant-ui/thread/changed-files'
+import { WIDGET_SHELL_CLASS } from '@/components/chat/widget-shell'
+import { DiffCount } from '@/components/ui/diff-count'
+import { FileTypeIcon } from '@/components/ui/file-type-icon'
+import { useI18n } from '@/i18n'
+import { cn } from '@/lib/utils'
+import { openReviewForPath, revealReview } from '@/store/review'
+
+/**
+ * Cursor-style "N files changed" summary closing out the newest assistant turn:
+ * one row per file it edited with that file's +/-, and a Review action opening
+ * the diff pane (⌘G). A row click opens that file's diff directly.
+ *
+ * Wears the shared `WIDGET_SHELL_CLASS` so it reads as the same panel as the
+ * transcript's other inline widgets rather than inventing its own chrome.
+ */
+export const ChangedFilesCard: FC<{ parts: readonly unknown[] }> = ({ parts }) => {
+  const { t } = useI18n()
+  const copy = t.assistant.thread
+  const files = useMemo(() => deriveChangedFiles(parts), [parts])
+
+  if (files.length === 0) {
+    return null
+  }
+
+  return (
+    <div
+      className={cn(WIDGET_SHELL_CLASS, 'mt-1.5 text-[length:var(--conversation-tool-font-size)]')}
+      data-slot="aui_changed-files"
+    >
+      <div className="flex items-center gap-2">
+        <span className="min-w-0 flex-1 truncate text-(--ui-text-primary)">{copy.filesChanged(files.length)}</span>
+        <button
+          className="shrink-0 cursor-pointer text-(--ui-text-tertiary) transition-colors hover:text-(--ui-text-primary)"
+          onClick={revealReview}
+          type="button"
+        >
+          {copy.reviewChanges}
+        </button>
+      </div>
+      <div className="mt-1.5 flex flex-col">
+        {files.map(file => (
+          <button
+            className="row-hover -mx-1.5 flex items-center gap-2 rounded-md px-1.5 py-1 text-left"
+            key={file.path}
+            onClick={() => void openReviewForPath(file.path)}
+            title={file.path}
+            type="button"
+          >
+            <FileTypeIcon className="shrink-0 text-(--ui-text-tertiary)" path={file.path} size="0.875rem" />
+            <span className="min-w-0 flex-1 truncate text-(--ui-text-secondary)">{file.name}</span>
+            <DiffCount added={file.added} removed={file.removed} />
+          </button>
+        ))}
+      </div>
+    </div>
+  )
+}

apps/desktop/src/components/assistant-ui/thread/changed-files.ts

@@ -0,0 +1,69 @@
+// Pure derivation for the assistant message's "N files changed" card: fold a
+// turn's file-edit tool parts into one row per file. No React/DOM.
+
+import {
+  countDiffLineStats,
+  fileEditBasename,
+  fileEditPath,
+  inlineDiffFromResult,
+  isFileEditTool,
+  parseMaybeObject
+} from '@/components/assistant-ui/tool/fallback-model'
+
+export interface ChangedFile {
+  added: number
+  /** Basename, for the row label. */
+  name: string
+  /** Path exactly as the tool reported it (absolute or repo-relative). */
+  path: string
+  removed: number
+}
+
+interface ChangedFilePart {
+  args?: unknown
+  result?: unknown
+  toolName?: unknown
+  type?: unknown
+}
+
+/**
+ * One row per file the turn edited, in first-touched order, with the +/- of
+ * every edit to that file summed. Only landed edits with a diff count: a call
+ * still running has no result, and a failed one changed nothing.
+ */
+export function deriveChangedFiles(parts: readonly unknown[]): ChangedFile[] {
+  const byPath = new Map<string, ChangedFile>()
+
+  for (const raw of parts) {
+    const part = (raw ?? {}) as ChangedFilePart
+
+    if (part.type !== 'tool-call' || typeof part.toolName !== 'string' || !isFileEditTool(part.toolName)) {
+      continue
+    }
+
+    const result = parseMaybeObject(part.result)
+    const diff = inlineDiffFromResult(result)
+
+    if (!diff) {
+      continue
+    }
+
+    const path = fileEditPath(parseMaybeObject(part.args), result)
+
+    if (!path) {
+      continue
+    }
+
+    const stats = countDiffLineStats(diff)
+    const existing = byPath.get(path)
+
+    if (existing) {
+      existing.added += stats.added
+      existing.removed += stats.removed
+    } else {
+      byPath.set(path, { added: stats.added, name: fileEditBasename(path), path, removed: stats.removed })
+    }
+  }
+
+  return [...byPath.values()]
+}

apps/desktop/src/components/assistant-ui/tool/fallback-model/index.ts

@@ -57,7 +57,7 @@ export function countDiffLineStats(diff: string): DiffLineStats {
   return { added, removed }
 }
 
-function fileEditPath(args: Record<string, unknown>, result: Record<string, unknown>): string {
+export function fileEditPath(args: Record<string, unknown>, result: Record<string, unknown>): string {
   return (
     firstStringField(args, ['path', 'file', 'filepath']) ||
     firstStringField(result, ['path', 'file', 'filepath', 'resolved_path']) ||

apps/desktop/src/i18n/ar.ts

@@ -2289,6 +2289,8 @@ export const ar = defineLocale({
       branchNewChat: 'تفريع إلى محادثة جديدة',
       react: 'تفاعل',
       dismissError: 'تجاهل الخطأ',
+      filesChanged: count => `${count} ملفات تم تغييرها`,
+      reviewChanges: 'مراجعة',
       readAloudFailed: 'فشلت القراءة بصوت عال',
       preparingAudio: 'جار تجهيز الصوت',
       stopReading: 'إيقاف القراءة',

apps/desktop/src/i18n/en.ts

@@ -2712,6 +2712,8 @@ export const en: Translations = {
       branchNewChat: 'Branch in new chat',
       react: 'React',
       dismissError: 'Dismiss error',
+      filesChanged: count => (count === 1 ? '1 file changed' : `${count} files changed`),
+      reviewChanges: 'Review',
       readAloudFailed: 'Read aloud failed',
       preparingAudio: 'Preparing audio...',
       stopReading: 'Stop reading',

apps/desktop/src/i18n/ja.ts

@@ -2538,6 +2538,8 @@ export const ja = defineLocale({
       branchNewChat: '新しいチャットでブランチ',
       react: 'リアクション',
       dismissError: 'エラーを閉じる',
+      filesChanged: count => `${count} 件のファイルを変更`,
+      reviewChanges: 'レビュー',
       readAloudFailed: '読み上げに失敗しました',
       preparingAudio: '音声を準備中...',
       stopReading: '読み上げを停止',

apps/desktop/src/i18n/types.ts

@@ -2309,6 +2309,8 @@ export interface Translations {
       branchNewChat: string
       react: string
       dismissError: string
+      filesChanged: (count: number) => string
+      reviewChanges: string
       readAloudFailed: string
       preparingAudio: string
       stopReading: string

apps/desktop/src/i18n/zh-hant.ts

@@ -2456,6 +2456,8 @@ export const zhHant = defineLocale({
       branchNewChat: '在新聊天中分支',
       react: '回應',
       dismissError: '关闭错误',
+      filesChanged: count => `${count} 個檔案已變更`,
+      reviewChanges: '檢視',
       readAloudFailed: '朗讀失敗',
       preparingAudio: '正在準備音訊...',
       stopReading: '停止朗讀',

apps/desktop/src/i18n/zh.ts

@@ -2888,6 +2888,8 @@ export const zh: Translations = {
       branchNewChat: '在新对话中分支',
       react: '回应',
       dismissError: '关闭错误',
+      filesChanged: count => `${count} 个文件已更改`,
+      reviewChanges: '查看',
       readAloudFailed: '朗读失败',
       preparingAudio: '正在准备音频...',
       stopReading: '停止朗读',

apps/desktop/src/store/review.ts

@@ -274,8 +274,62 @@ export function toggleReview(): void {
   if ($reviewOpen.get()) {
     closeReview()
   } else {
+    revealReview()
+  }
+}
+
+/**
+ * Open the review pane and bring it into view. Unlike `toggleReview` this never
+ * closes an already-open pane — it's the "take me to the diff" entry point used
+ * by the transcript's changed-files card.
+ */
+export function revealReview(): void {
+  const wasOpen = $reviewOpen.get()
+
+  if (!wasOpen) {
     openReview()
-    revealTreePane(REVIEW_PANE_ID)
+  }
+
+  if (matchesQuery(SIDEBAR_COLLAPSE_MEDIA_QUERY)) {
+    // The reveal pin is a toggle, so only fire it when the overlay isn't
+    // already slid in — otherwise "show me the diff" would hide the pane.
+    if (!wasOpen) {
+      window.dispatchEvent(new CustomEvent(PANE_TOGGLE_REVEAL_EVENT, { detail: { id: REVIEW_PANE_ID } }))
+    }
+
+    return
+  }
+
+  revealTreePane(REVIEW_PANE_ID)
+}
+
+/** The changed file matching a tool-reported path (absolute or repo-relative). */
+function matchReviewFile(files: readonly HermesReviewFile[], path: string): HermesReviewFile | undefined {
+  const target = path.replace(/\\/g, '/').replace(/\/+$/, '')
+
+  if (!target) {
+    return undefined
+  }
+
+  return files.find(file => {
+    const candidate = file.path.replace(/\\/g, '/')
+
+    return candidate === target || target.endsWith(`/${candidate}`) || candidate.endsWith(`/${target}`)
+  })
+}
+
+/**
+ * Open the review pane on one file's diff. The path comes from a tool call, so
+ * it may be absolute while git reports repo-relative — match on the tail.
+ */
+export async function openReviewForPath(path: string): Promise<void> {
+  revealReview()
+  await refreshReview()
+
+  const file = matchReviewFile($reviewFiles.get(), path)
+
+  if (file) {
+    await selectReviewFile(file)
   }
 }