diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index f5ea5bb1eba..70bbc296288 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -2112,12 +2112,13 @@ function ChatViewContent(props: ChatViewProps) {
         worktreePath: activeThread?.worktreePath ?? null,
       })
     : null;
+  const gitStatusCwd = activeThread?.worktreePath ?? gitCwd;
   const gitStatusQuery = useEnvironmentQuery(
-    gitCwd === null
+    gitStatusCwd === null
       ? null
       : vcsEnvironment.status({
           environmentId,
-          input: { cwd: gitCwd },
+          input: { cwd: gitStatusCwd },
         }),
   );
   const keybindings = useAtomValue(primaryServerKeybindingsAtom);
@@ -2151,6 +2152,9 @@ function ChatViewContent(props: ChatViewProps) {
     terminalUiLaunchContext?.threadId === activeThreadId ? terminalUiLaunchContext : null;
   // Default true while loading to avoid toolbar flicker.
   const isGitRepo = gitStatusQuery.data?.isRepo ?? true;
+  const initialDiffPanelGitScope =
+    gitStatusQuery.data?.hasWorkingTreeChanges === true ? "unstaged" : "branch";
+  const diffPanelGitStatusResolutionKey = gitStatusQuery.data ? "resolved" : "pending";
   const terminalShortcutLabelOptions = useMemo(
     () => ({
       context: {
@@ -4968,7 +4972,12 @@ function ChatViewContent(props: ChatViewProps) {
       />
     ) : activeRightPanelSurface?.kind === "diff" ? (
       <Suspense fallback={null}>
-        <DiffPanel mode="embedded" composerDraftTarget={composerDraftTarget} />
+        <DiffPanel
+          key={`${activeThreadKey}:${diffPanelGitStatusResolutionKey}`}
+          mode="embedded"
+          composerDraftTarget={composerDraftTarget}
+          initialGitScope={initialDiffPanelGitScope}
+        />
       </Suspense>
     ) : activeRightPanelSurface?.kind === "plan" ? (
       <PlanSidebar
diff --git a/apps/web/src/components/DiffPanel.tsx b/apps/web/src/components/DiffPanel.tsx
index cbcd36ce05e..5cb2a1cfdea 100644
--- a/apps/web/src/components/DiffPanel.tsx
+++ b/apps/web/src/components/DiffPanel.tsx
@@ -178,13 +178,19 @@ const DIFF_PANEL_UNSAFE_CSS = `
 interface DiffPanelProps {
   mode?: DiffPanelMode;
   composerDraftTarget: ScopedThreadRef | DraftId;
+  initialGitScope: "branch" | "unstaged";
 }
 
 export { DiffWorkerPoolProvider } from "./DiffWorkerPoolProvider";
 
-export default function DiffPanel({ mode = "inline", composerDraftTarget }: DiffPanelProps) {
+export default function DiffPanel({
+  mode = "inline",
+  composerDraftTarget,
+  initialGitScope: initialGitScopeProp,
+}: DiffPanelProps) {
   const { resolvedTheme } = useTheme();
   const settings = useClientSettings();
+  const [initialGitScope] = useState(initialGitScopeProp);
   const [diffRenderMode, setDiffRenderMode] = useState<DiffRenderMode>("stacked");
   const [wordWrap, setWordWrap] = useState(settings.wordWrap);
   const [diffIgnoreWhitespace, setDiffIgnoreWhitespace] = useState(settings.diffIgnoreWhitespace);
@@ -199,9 +205,6 @@ export default function DiffPanel({ mode = "inline", composerDraftTarget }: Diff
     strict: false,
     select: (params) => resolveThreadRouteRef(params),
   });
-  const diffSelection = useDiffPanelStore((state) =>
-    selectThreadDiffPanelSelection(state.byThreadKey, routeThreadRef),
-  );
   const activeThreadId = routeThreadRef?.threadId ?? null;
   const activeThread = useThread(routeThreadRef);
   const activeProjectId = activeThread?.projectId ?? null;
@@ -229,6 +232,13 @@ export default function DiffPanel({ mode = "inline", composerDraftTarget }: Diff
         })
       : null,
   );
+  const diffSelection = useDiffPanelStore((state) =>
+    selectThreadDiffPanelSelection(
+      state.byThreadKey,
+      routeThreadRef,
+      initialGitScope === "unstaged",
+    ),
+  );
   const isGitRepo = gitStatusQuery.data?.isRepo ?? true;
   const { turnDiffSummaries, inferredCheckpointTurnCountByTurnId } =
     useTurnDiffSummaries(activeThread);
diff --git a/apps/web/src/diffPanelStore.test.ts b/apps/web/src/diffPanelStore.test.ts
index 64846e8e9f1..607b7c8d580 100644
--- a/apps/web/src/diffPanelStore.test.ts
+++ b/apps/web/src/diffPanelStore.test.ts
@@ -9,12 +9,26 @@ const THREAD_REF = scopeThreadRef(EnvironmentId.make("environment-1"), ThreadId.
 describe("diffPanelStore", () => {
   beforeEach(() => useDiffPanelStore.setState({ byThreadKey: {}, branchBaseRefByThreadKey: {} }));
 
-  it("defaults each thread to branch changes with automatic base selection", () => {
+  it("defaults each thread to branch changes when the working tree is clean", () => {
     expect(
       selectThreadDiffPanelSelection(useDiffPanelStore.getState().byThreadKey, THREAD_REF),
     ).toEqual({ kind: "branch", baseRef: null });
   });
 
+  it("defaults each thread to working changes when the working tree is dirty", () => {
+    expect(
+      selectThreadDiffPanelSelection(useDiffPanelStore.getState().byThreadKey, THREAD_REF, true),
+    ).toEqual({ kind: "unstaged" });
+  });
+
+  it("preserves an explicit scope selection when the working tree state changes", () => {
+    useDiffPanelStore.getState().selectGitScope(THREAD_REF, "branch");
+
+    expect(
+      selectThreadDiffPanelSelection(useDiffPanelStore.getState().byThreadKey, THREAD_REF, true),
+    ).toEqual({ kind: "branch", baseRef: null });
+  });
+
   it("clears incompatible selection fields when changing scopes", () => {
     const store = useDiffPanelStore.getState();
     store.selectTurn(THREAD_REF, TurnId.make("turn-1"), "src/app.ts");
diff --git a/apps/web/src/diffPanelStore.ts b/apps/web/src/diffPanelStore.ts
index c946b286d1b..56b5ad23fec 100644
--- a/apps/web/src/diffPanelStore.ts
+++ b/apps/web/src/diffPanelStore.ts
@@ -11,6 +11,7 @@ export type DiffPanelSelection =
   | { kind: "turn"; turnId: TurnId; filePath: string | null; revealRequestId: number };
 
 const DEFAULT_SELECTION: DiffPanelSelection = { kind: "branch", baseRef: null };
+const DEFAULT_WORKING_TREE_SELECTION: DiffPanelSelection = { kind: "unstaged" };
 
 interface DiffPanelStoreState {
   byThreadKey: Record<string, DiffPanelSelection>;
@@ -133,7 +134,11 @@ export const useDiffPanelStore = create<DiffPanelStoreState>()(
 export function selectThreadDiffPanelSelection(
   byThreadKey: Record<string, DiffPanelSelection>,
   ref: ScopedThreadRef | null | undefined,
+  hasWorkingTreeChanges = false,
 ): DiffPanelSelection {
   if (!ref) return DEFAULT_SELECTION;
-  return byThreadKey[scopedThreadKey(ref)] ?? DEFAULT_SELECTION;
+  return (
+    byThreadKey[scopedThreadKey(ref)] ??
+    (hasWorkingTreeChanges ? DEFAULT_WORKING_TREE_SELECTION : DEFAULT_SELECTION)
+  );
 }