fix(web): add default thread env mode setting

apps/web/src/appSettings.test.ts

@@ -1,12 +1,55 @@
-import { describe, expect, it } from "vitest";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
 import {
+  getAppSettingsSnapshot,
   getAppModelOptions,
   getSlashModelOptions,
   normalizeCustomModelSlugs,
   resolveAppModelSelection,
 } from "./appSettings";
 
+function createStorage() {
+  const values = new Map<string, string>();
+  return {
+    getItem: (key: string) => values.get(key) ?? null,
+    setItem: (key: string, value: string) => {
+      values.set(key, value);
+    },
+    removeItem: (key: string) => {
+      values.delete(key);
+    },
+    clear: () => {
+      values.clear();
+    },
+  };
+}
+
+function writeSettings(partial: Record<string, unknown>) {
+  localStorage.setItem(
+    "t3code:app-settings:v1",
+    JSON.stringify({
+      codexBinaryPath: "",
+      codexHomePath: "",
+      confirmThreadDelete: true,
+      enableAssistantStreaming: false,
+      customCodexModels: [],
+      ...partial,
+    }),
+  );
+}
+
+beforeEach(() => {
+  const storage = createStorage();
+  vi.stubGlobal("localStorage", storage);
+  vi.stubGlobal("window", {
+    localStorage: storage,
+  });
+});
+
+afterEach(() => {
+  vi.unstubAllGlobals();
+});
+
 describe("normalizeCustomModelSlugs", () => {
   it("normalizes aliases, removes built-ins, and deduplicates values", () => {
     expect(
@@ -72,3 +115,36 @@ describe("getSlashModelOptions", () => {
     expect(options.map((option) => option.slug)).toEqual(["openai/gpt-oss-120b"]);
   });
 });
+
+describe("getAppSettingsSnapshot", () => {
+  it("defaults the thread environment mode to local for older persisted settings", () => {
+    localStorage.setItem(
+      "t3code:app-settings:v1",
+      JSON.stringify({
+        codexBinaryPath: "/usr/local/bin/codex",
+        codexHomePath: "",
+        confirmThreadDelete: true,
+        enableAssistantStreaming: false,
+        customCodexModels: [],
+      }),
+    );
+
+    expect(getAppSettingsSnapshot().defaultThreadEnvMode).toBe("local");
+  });
+
+  it("falls back to local when the persisted thread environment mode is invalid", () => {
+    writeSettings({
+      defaultThreadEnvMode: "invalid",
+    });
+
+    expect(getAppSettingsSnapshot().defaultThreadEnvMode).toBe("local");
+  });
+
+  it("reads a persisted worktree default for new threads", () => {
+    writeSettings({
+      defaultThreadEnvMode: "worktree",
+    });
+
+    expect(getAppSettingsSnapshot().defaultThreadEnvMode).toBe("worktree");
+  });
+});

apps/web/src/appSettings.ts

@@ -17,6 +17,9 @@ const AppSettingsSchema = Schema.Struct({
   codexHomePath: Schema.String.check(Schema.isMaxLength(4096)).pipe(
     Schema.withConstructorDefault(() => Option.some("")),
   ),
+  defaultThreadEnvMode: Schema.Literals(["local", "worktree"]).pipe(
+    Schema.withConstructorDefault(() => Option.some("local")),
+  ),
   confirmThreadDelete: Schema.Boolean.pipe(Schema.withConstructorDefault(() => Option.some(true))),
   enableAssistantStreaming: Schema.Boolean.pipe(
     Schema.withConstructorDefault(() => Option.some(false)),

apps/web/src/components/Sidebar.logic.test.ts

@@ -2,6 +2,7 @@ import { describe, expect, it } from "vitest";
 
 import {
   hasUnseenCompletion,
+  resolveSidebarNewThreadEnvMode,
   resolveThreadStatusPill,
   shouldClearThreadSelectionOnMouseDown,
 } from "./Sidebar.logic";
@@ -62,6 +63,25 @@ describe("shouldClearThreadSelectionOnMouseDown", () => {
   });
 });
 
+describe("resolveSidebarNewThreadEnvMode", () => {
+  it("uses the app default when the caller does not request a specific mode", () => {
+    expect(
+      resolveSidebarNewThreadEnvMode({
+        defaultEnvMode: "worktree",
+      }),
+    ).toBe("worktree");
+  });
+
+  it("preserves an explicit requested mode over the app default", () => {
+    expect(
+      resolveSidebarNewThreadEnvMode({
+        requestedEnvMode: "local",
+        defaultEnvMode: "worktree",
+      }),
+    ).toBe("local");
+  });
+});
+
 describe("resolveThreadStatusPill", () => {
   const baseThread = {
     interactionMode: "plan" as const,

apps/web/src/components/Sidebar.logic.ts

@@ -2,6 +2,7 @@ import type { Thread } from "../types";
 import { findLatestProposedPlan, isLatestTurnSettled } from "../session-logic";
 
 export const THREAD_SELECTION_SAFE_SELECTOR = "[data-thread-item], [data-thread-selection-safe]";
+export type SidebarNewThreadEnvMode = "local" | "worktree";
 
 export interface ThreadStatusPill {
   label:
@@ -37,6 +38,13 @@ export function shouldClearThreadSelectionOnMouseDown(target: HTMLElement | null
   return !target.closest(THREAD_SELECTION_SAFE_SELECTOR);
 }
 
+export function resolveSidebarNewThreadEnvMode(input: {
+  requestedEnvMode?: SidebarNewThreadEnvMode;
+  defaultEnvMode: SidebarNewThreadEnvMode;
+}): SidebarNewThreadEnvMode {
+  return input.requestedEnvMode ?? input.defaultEnvMode;
+}
+
 export function resolveThreadStatusPill(input: {
   thread: ThreadStatusInput;
   hasPendingApprovals: boolean;

apps/web/src/components/Sidebar.tsx

@@ -83,7 +83,11 @@ import {
 import { useThreadSelectionStore } from "../threadSelectionStore";
 import { formatWorktreePathForDisplay, getOrphanedWorktreePathForThread } from "../worktreeCleanup";
 import { isNonEmpty as isNonEmptyString } from "effect/String";
-import { resolveThreadStatusPill, shouldClearThreadSelectionOnMouseDown } from "./Sidebar.logic";
+import {
+  resolveSidebarNewThreadEnvMode,
+  resolveThreadStatusPill,
+  shouldClearThreadSelectionOnMouseDown,
+} from "./Sidebar.logic";
 
 const EMPTY_KEYBINDINGS: ResolvedKeybindingsConfig = [];
 const THREAD_PREVIEW_LIMIT = 6;
@@ -310,6 +314,7 @@ export default function Sidebar() {
   const setSelectionAnchor = useThreadSelectionStore((s) => s.setAnchor);
   const shouldBrowseForProjectImmediately = isElectron;
   const shouldShowProjectPathEntry = addingProject && !shouldBrowseForProjectImmediately;
+  const defaultNewThreadEnvMode = appSettings.defaultThreadEnvMode;
   const pendingApprovalByThreadId = useMemo(() => {
     const map = new Map<ThreadId, boolean>();
     for (const thread of threads) {
@@ -451,7 +456,7 @@ export default function Sidebar() {
           createdAt,
           branch: options?.branch ?? null,
           worktreePath: options?.worktreePath ?? null,
-          envMode: options?.envMode ?? "local",
+          envMode: options?.envMode ?? appSettings.defaultThreadEnvMode,
           runtimeMode: DEFAULT_RUNTIME_MODE,
         });
 
@@ -469,6 +474,7 @@ export default function Sidebar() {
       routeThreadId,
       setDraftThreadContext,
       setProjectDraftThreadId,
+      appSettings.defaultThreadEnvMode,
     ],
   );
 
@@ -526,7 +532,9 @@ export default function Sidebar() {
           defaultModel: DEFAULT_MODEL_BY_PROVIDER.codex,
           createdAt,
         });
-        await handleNewThread(projectId).catch(() => undefined);
+        await handleNewThread(projectId, {
+          envMode: defaultNewThreadEnvMode,
+        }).catch(() => undefined);
       } catch (error) {
         const description =
           error instanceof Error ? error.message : "An error occurred while adding the project.";
@@ -545,6 +553,7 @@ export default function Sidebar() {
       finishAddingProject();
     },
     [
+      defaultNewThreadEnvMode,
       focusMostRecentThreadForProject,
       handleNewThread,
       isAddingProject,
@@ -1053,7 +1062,9 @@ export default function Sidebar() {
           activeThread?.projectId ?? activeDraftThread?.projectId ?? projects[0]?.id;
         if (!projectId) return;
         event.preventDefault();
-        void handleNewThread(projectId);
+        void handleNewThread(projectId, {
+          envMode: "local",
+        });
         return;
       }
 
@@ -1485,7 +1496,11 @@ export default function Sidebar() {
                                     onClick={(event) => {
                                       event.preventDefault();
                                       event.stopPropagation();
-                                      void handleNewThread(project.id);
+                                      void handleNewThread(project.id, {
+                                        envMode: resolveSidebarNewThreadEnvMode({
+                                          defaultEnvMode: defaultNewThreadEnvMode,
+                                        }),
+                                      });
                                     }}
                                   >
                                     <SquarePenIcon className="size-3.5" />

apps/web/src/components/ui/switch.tsx

@@ -8,7 +8,7 @@ function Switch({ className, ...props }: SwitchPrimitive.Root.Props) {
   return (
     <SwitchPrimitive.Root
       className={cn(
-        "inline-flex h-[calc(var(--thumb-size)+2px)] w-[calc(var(--thumb-size)*2-2px)] shrink-0 items-center rounded-full p-px outline-none transition-[background-color,box-shadow] duration-200 [--thumb-size:--spacing(5)] focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1 focus-visible:ring-offset-background data-checked:bg-primary data-unchecked:bg-input data-disabled:opacity-64 sm:[--thumb-size:--spacing(4)]",
+        "inline-flex h-[calc(var(--thumb-size)+2px)] w-[calc(var(--thumb-size)*2-2px)] shrink-0 cursor-pointer items-center rounded-full p-px outline-none transition-[background-color,box-shadow] duration-200 [--thumb-size:--spacing(5)] focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-1 focus-visible:ring-offset-background data-checked:bg-primary data-unchecked:bg-input data-disabled:cursor-not-allowed data-disabled:opacity-64 sm:[--thumb-size:--spacing(4)]",
         className,
       )}
       data-slot="switch"

apps/web/src/routes/_chat.settings.tsx

@@ -437,6 +437,49 @@ function SettingsRouteView() {
               </div>
             </section>
 
+            <section className="rounded-2xl border border-border bg-card p-5">
+              <div className="mb-4">
+                <h2 className="text-sm font-medium text-foreground">Threads</h2>
+                <p className="mt-1 text-xs text-muted-foreground">
+                  Choose the default workspace mode for newly created draft threads.
+                </p>
+              </div>
+
+              <div className="flex items-center justify-between rounded-lg border border-border bg-background px-3 py-2">
+                <div>
+                  <p className="text-sm font-medium text-foreground">Default to New worktree</p>
+                  <p className="text-xs text-muted-foreground">
+                    New threads start in New worktree mode instead of Local.
+                  </p>
+                </div>
+                <Switch
+                  checked={settings.defaultThreadEnvMode === "worktree"}
+                  onCheckedChange={(checked) =>
+                    updateSettings({
+                      defaultThreadEnvMode: checked ? "worktree" : "local",
+                    })
+                  }
+                  aria-label="Default new threads to New worktree mode"
+                />
+              </div>
+
+              {settings.defaultThreadEnvMode !== defaults.defaultThreadEnvMode ? (
+                <div className="mt-3 flex justify-end">
+                  <Button
+                    size="xs"
+                    variant="outline"
+                    onClick={() =>
+                      updateSettings({
+                        defaultThreadEnvMode: defaults.defaultThreadEnvMode,
+                      })
+                    }
+                  >
+                    Restore default
+                  </Button>
+                </div>
+              ) : null}
+            </section>
+
             <section className="rounded-2xl border border-border bg-card p-5">
               <div className="mb-4">
                 <h2 className="text-sm font-medium text-foreground">Responses</h2>