feat: continue an existing local or remote branch in a new worktree

apps/mobile/src/features/threads/NewTaskContextPickerScreens.tsx

@@ -345,7 +345,6 @@ export function NewTaskBranchPickerRouteScreen() {
               startFromOrigin: flow.startFromOrigin,
               onChangeStartFromOrigin: flow.setStartFromOrigin,
               createNewBranch: flow.createNewBranch,
-              onChangeCreateNewBranch: flow.setCreateNewBranch,
             }
           : undefined
       }
@@ -371,9 +370,8 @@ export function BranchPickerScreen(props: {
   readonly worktree?: {
     readonly startFromOrigin: boolean;
     readonly onChangeStartFromOrigin: (value: boolean) => void;
-    /** Scheduled tasks omit these: a recurring run would find its branch still checked out. */
+    /** Scheduled tasks omit this: a recurring run would find its branch still checked out. */
     readonly createNewBranch?: boolean;
-    readonly onChangeCreateNewBranch?: ((value: boolean) => void) | null;
   };
 }) {
   const searchRef = useRef<import("react-native").TextInputInstance>(null);
@@ -422,16 +420,10 @@ export function BranchPickerScreen(props: {
         Platform.OS === "android" ? "rounded-[28px]" : "rounded-2xl",
       )}
     >
-      {worktree.onChangeCreateNewBranch ? (
-        <ToggleRow
-          onValueChange={worktree.onChangeCreateNewBranch}
-          title="Create new branch"
-          value={!checksOutExistingBranch}
-        />
-      ) : null}
       {checksOutExistingBranch ? (
-        <Text className="bg-grouped-card px-4 pb-3 text-sm text-foreground-muted">
-          Select a local branch that is not already checked out.
+        <Text className="bg-grouped-card px-4 py-3 text-sm text-foreground-muted">
+          Select a branch that is not already checked out. A remote branch is checked out as a local
+          branch that tracks it.
         </Text>
       ) : (
         <ToggleRow

apps/mobile/src/features/threads/NewTaskDraftScreen.tsx

@@ -89,6 +89,7 @@ import { resolveDraftProjectSelection } from "./new-task-project-selection";
 import {
   resolveNewTaskBranchLabel,
   resolveNewTaskWorkspaceLabel,
+  resolveNextNewTaskWorkspace,
 } from "./new-task-context-presentation";
 import { incomingShareImports, useIncomingShare } from "../sharing/IncomingShareProvider";
 import { idleShareFlagAtom, idleShareImportPhaseAtom } from "./incomingShareImport";
@@ -544,7 +545,9 @@ export function NewTaskDraftScreen(props: {
   const workspaceLabel = resolveNewTaskWorkspaceLabel({
     workspaceMode: flow.workspaceMode,
     worktreePath: flow.selectedWorktreePath,
+    createNewBranch: flow.createNewBranch,
   });
+  const nextWorkspace = resolveNextNewTaskWorkspace(flow);
   const showBranchLoading =
     environmentConnected && flow.branchesLoading && flow.availableBranches.length === 0;
 
@@ -822,7 +825,7 @@ export function NewTaskDraftScreen(props: {
   const workspaceControls = (
     <View className="flex-row items-center gap-1 px-2">
       <ComposerInlineControl
-        accessibilityHint={`Switches to ${flow.workspaceMode === "local" ? "a new worktree" : "the current checkout"}`}
+        accessibilityHint={`Switches to ${resolveNewTaskWorkspaceLabel({ workspaceMode: nextWorkspace.mode, worktreePath: null, createNewBranch: nextWorkspace.createNewBranch !== false })}`}
         accessibilityLabel={workspaceLabel}
         disabled={isComposerInteractionLocked || !flow.isGitRepo}
         renderIcon={(size) => (
@@ -834,13 +837,13 @@ export function NewTaskDraftScreen(props: {
         )}
         label={workspaceLabel}
         maxWidth="100%"
-        onPress={() => flow.setWorkspaceMode(flow.workspaceMode === "local" ? "worktree" : "local")}
+        onPress={() => flow.setWorkspaceMode(nextWorkspace.mode, nextWorkspace.createNewBranch)}
         showChevron={false}
       />
 
       <View className="min-w-0 shrink">
         <ComposerInlineControl
-          accessibilityLabel={`${flow.workspaceMode === "worktree" ? "Base branch" : "Branch"}: ${selectedBranchLabel}`}
+          accessibilityLabel={`${flow.workspaceMode === "worktree" && flow.createNewBranch ? "Base branch" : "Branch"}: ${selectedBranchLabel}`}
           chevronDirection="right"
           disabled={isComposerInteractionLocked || !flow.isGitRepo}
           icon="arrow.triangle.branch"

apps/mobile/src/features/threads/new-task-context-presentation.ts

@@ -19,13 +19,30 @@ export function resolveNewTaskWorkspaceSelection(input: {
 export function resolveNewTaskWorkspaceLabel(input: {
   readonly workspaceMode: WorkspaceMode;
   readonly worktreePath: string | null;
-}): "Current checkout" | "Current worktree" | "New worktree" {
+  readonly createNewBranch?: boolean;
+}): "Current checkout" | "Current worktree" | "New worktree" | "Check out in worktree" {
   if (input.workspaceMode === "worktree") {
-    return "New worktree";
+    return input.createNewBranch === false ? "Check out in worktree" : "New worktree";
   }
   return input.worktreePath ? "Current worktree" : "Current checkout";
 }
 
+/** The workspace control cycles Current checkout, New worktree, then Check out in worktree. */
+export function resolveNextNewTaskWorkspace(input: {
+  readonly workspaceMode: WorkspaceMode;
+  readonly createNewBranch: boolean;
+  readonly canCheckoutWorktree: boolean;
+}): { readonly mode: WorkspaceMode; readonly createNewBranch?: boolean } {
+  if (input.workspaceMode === "local") {
+    return input.canCheckoutWorktree
+      ? { mode: "worktree", createNewBranch: true }
+      : { mode: "worktree" };
+  }
+  return input.canCheckoutWorktree && input.createNewBranch
+    ? { mode: "worktree", createNewBranch: false }
+    : { mode: "local" };
+}
+
 export function resolveNewTaskBranchWorktreePath(input: {
   readonly workspaceMode: WorkspaceMode;
   readonly projectCwd: string;

apps/mobile/src/features/threads/new-task-flow-provider.tsx

@@ -148,8 +148,10 @@ type NewTaskFlowContextValue = {
     selection: ComposerDraftWorkspaceSelection | undefined,
   ) => ComposerDraftWorkspaceSelection;
   readonly startFromOrigin: boolean;
-  /** False checks out the selected local branch itself in the new worktree. */
+  /** False checks out the selected branch itself in the new worktree. */
   readonly createNewBranch: boolean;
+  /** Whether the server can check out an existing branch in a new worktree. */
+  readonly canCheckoutWorktree: boolean;
   readonly pullRequestReference: string | undefined;
   readonly draftKey: string | null;
   readonly prompt: string;
@@ -191,11 +193,10 @@ type NewTaskFlowContextValue = {
     key: string | null,
     options?: ReadonlyArray<ProviderOptionSelection>,
   ) => void;
-  readonly setWorkspaceMode: (mode: WorkspaceMode) => void;
+  /** `createNewBranch` false checks out the selected branch in the new worktree. */
+  readonly setWorkspaceMode: (mode: WorkspaceMode, createNewBranch?: boolean) => void;
   readonly selectBranch: (branch: VcsRef) => void;
   readonly setStartFromOrigin: (value: boolean) => void;
-  /** Null when the server cannot check out an existing branch, which hides the toggle. */
-  readonly setCreateNewBranch: ((value: boolean) => void) | null;
   readonly buildPendingTaskMessage: (
     metadata: TurnCommandMetadata,
     options?: {
@@ -648,7 +649,7 @@ export function NewTaskFlowProvider(
     return false;
   };
 
-  const setWorkspaceMode = (mode: WorkspaceMode) => {
+  const setWorkspaceMode = (mode: WorkspaceMode, nextCreateNewBranch?: boolean) => {
     if (!selectedProjectDraftKey) {
       return;
     }
@@ -666,13 +667,15 @@ export function NewTaskFlowProvider(
           mode === "local"
             ? localSelection.branch
             : resolveNewTaskWorktreeBranch({
-                createNewBranch,
+                createNewBranch: nextCreateNewBranch ?? createNewBranch,
                 selectedBranchName,
-                branches: availableBranches,
+                branches: allBranchRefs,
               }),
         worktreePath: mode === "local" ? localSelection.worktreePath : selectedWorktreePath,
         ...(draftStartFromOrigin !== undefined ? { startFromOrigin: draftStartFromOrigin } : {}),
-        ...(draftCreateNewBranch !== undefined ? { createNewBranch: draftCreateNewBranch } : {}),
+        ...((nextCreateNewBranch ?? draftCreateNewBranch) !== undefined
+          ? { createNewBranch: nextCreateNewBranch ?? draftCreateNewBranch }
+          : {}),
         // Refs have not named the current branch yet; the selection follows it.
         ...(mode === "local" && localSelection.awaitsCurrentBranch
           ? { followsCurrentCheckout: true }
@@ -718,26 +721,6 @@ export function NewTaskFlowProvider(
     });
   };
 
-  const updateCreateNewBranch = (value: boolean) => {
-    if (!selectedProjectDraftKey) {
-      return;
-    }
-    updateComposerDraftSettings(selectedProjectDraftKey, {
-      workspaceSelection: {
-        mode: workspaceMode,
-        branch: resolveNewTaskWorktreeBranch({
-          createNewBranch: value,
-          selectedBranchName,
-          branches: availableBranches,
-        }),
-        worktreePath: selectedWorktreePath,
-        ...(draftStartFromOrigin !== undefined ? { startFromOrigin: draftStartFromOrigin } : {}),
-        createNewBranch: value,
-      },
-    });
-  };
-  const setCreateNewBranch = supportsExistingBranchWorktree ? updateCreateNewBranch : null;
-
   const refreshBranches = branchState.refresh;
   const loadBranches = () => {
     if (!selectedProject) {
@@ -915,6 +898,7 @@ export function NewTaskFlowProvider(
     resolveWorkspaceSelection,
     startFromOrigin,
     createNewBranch,
+    canCheckoutWorktree: supportsExistingBranchWorktree,
     draftKey: selectedProjectDraftKey,
     pullRequestReference: selectedProjectDraft.workspaceSelection?.pullRequestReference,
     prompt,
@@ -947,7 +931,6 @@ export function NewTaskFlowProvider(
     setWorkspaceMode,
     selectBranch,
     setStartFromOrigin,
-    setCreateNewBranch,
     buildPendingTaskMessage,
     setPrompt,
     replaceAttachments,

apps/server/src/mcp/toolkits/project/handlers.test.ts

@@ -57,7 +57,7 @@ it.effect("reports a rejected existing-branch launch as an invalid request", ()
       deletedAt: null,
     } as OrchestrationV2ThreadShell;
     const message =
-      'Branch "main" is already checked out at /repo. Select another branch, or enable Create new branch.';
+      'Branch "main" is already checked out at /repo. Select another branch, or choose New worktree.';
     const dependencies = Layer.mergeAll(
       Layer.mock(ProviderRegistry.ProviderRegistry)({ getProviders: Effect.succeed([]) }),
       ServerSettings.layerTest(),