fix(web): find the fallback model in Settings search

apps/web/src/components/settings/ProjectDefaultsSettings.tsx

@@ -229,8 +229,7 @@ export function ProjectDefaultsSettings({ category }: { category: ProjectSetting
       serverScoped
       settingKeys={["fallbackModelSelection"]}
       mixed={mixedFallback}
-      id="fallback-model"
-      title="Fallback model"
+      {...searchableSetting("fallback-model")}
       description="Used for new threads when the default model's provider is out of usage."
       resetAction={
         mixedFallback || settings.fallbackModelSelection !== null ? (

apps/web/src/components/settings/ProjectSettingsPanel.browser.test.tsx

@@ -138,6 +138,7 @@ import { buildSidebarProjectSnapshots } from "../../sidebarProjectGrouping";
 import { ProjectSettingsPanel } from "./ProjectSettingsPanel";
 import { ProjectsSettings } from "./ProjectsSettings";
 import { SettingsScopeProvider } from "./SettingsScopeContext";
+import { SettingsScopeNotice } from "./SettingsScopeNotice";
 import { validateSettingsScopeSearch, type SettingsScopeSearch } from "./settingsScope";
 import { retainSettingsScope, validateSettingsRouteSearch } from "./settingsScopeNavigation";
 
@@ -533,6 +534,48 @@ describe("project identity reset", () => {
   });
 });
 
+it("opens the fallback search target across all environments from a checkout", async () => {
+  setup();
+  const root = createRootRoute();
+  const settings = createRoute({
+    getParentRoute: () => root,
+    path: "settings",
+    validateSearch: validateSettingsRouteSearch,
+    search: { middlewares: [retainSettingsScope] },
+  });
+  const threads = createRoute({
+    getParentRoute: () => settings,
+    path: "threads",
+    component: () => (
+      <SettingsScopeProvider search={settings.useSearch()} onChange={() => {}}>
+        <SettingsScopeNotice target="all" targetId="fallback-model">
+          Choose all environments to edit the fallback model.
+        </SettingsScopeNotice>
+      </SettingsScopeProvider>
+    ),
+  });
+  const query = new URLSearchParams({
+    project: projectKey(),
+    machine: primaryId,
+    checkout: "primary:/work/primary",
+  });
+  const router = createRouter({
+    routeTree: root.addChildren([settings.addChildren([threads])]),
+    history: createMemoryHistory({ initialEntries: [`/settings/threads?${query}#fallback-model`] }),
+  });
+  await router.load();
+  // This route needs the real scope-retention middleware used by settings search.
+  await using _screen = await render(
+    <RegistryContext.Provider value={appAtomRegistry}>
+      <RouterProvider router={router} />
+    </RegistryContext.Provider>,
+    { router: false },
+  );
+  await userEvent.click(page.getByRole("button", { name: "Open all environments" }));
+  await vi.waitFor(() => expect(router.state.location.search).toEqual({}));
+  expect(router.state.location.hash).toBe("fallback-model");
+});
+
 describe("project settings scope", () => {
   const environmentMenu = () => page.getByRole("button", { name: /^Environment scope:/ });
   const primaryOption = () => page.getByRole("menuitemradio", { name: /^primary/ });

apps/web/src/components/settings/SettingsScopeNotice.tsx

@@ -129,7 +129,16 @@ export function SettingsScopeNotice({
         )}
         onClick={() => {
           if (targetId)
-            void navigate({ to: pathname, search: () => choice.search, hash: targetId });
+            void navigate({
+              to: pathname,
+              search: () => ({
+                project: undefined,
+                machine: undefined,
+                checkout: undefined,
+                ...choice.search,
+              }),
+              hash: targetId,
+            });
           else selectScope(choice.search);
         }}
       >

apps/web/src/components/settings/settingsSearch.test.ts

@@ -64,6 +64,13 @@ describe("searchSettings", () => {
     expect(searchSettings("sharing", ITEMS).map((item) => item.id)).toEqual(["network-access"]);
     expect(searchSettings("claude", ITEMS).map((item) => item.id)).toEqual(["providers"]);
     expect(searchSettings("long lines", ITEMS).map((item) => item.id)).toEqual(["word-wrap"]);
+    for (const query of ["fallback", "fallback agent", "fallback model"]) {
+      expect(searchSettings(query)[0]).toMatchObject({
+        id: "fallback-model",
+        to: "/settings/threads",
+        scope: "environment-defaults",
+      });
+    }
   });
 
   it("hides the Secrets page from nav and search while the secrets feature is disabled", () => {
@@ -205,6 +212,11 @@ describe("settings search targets", () => {
     expect(isSettingsSearchScopeAvailable(updates.scope, "environment")).toBe(true);
     expect(isSettingsSearchScopeAvailable(updates.scope, "all")).toBe(true);
     expect(isSettingsSearchScopeAvailable(updates.scope, "project")).toBe(false);
+    const fallback = getSettingsSearchTargetScope("fallback-model")!;
+    expect(fallback.scope).toBe("environment-defaults");
+    expect(isSettingsSearchScopeAvailable(fallback.scope, "environment")).toBe(true);
+    expect(isSettingsSearchScopeAvailable(fallback.scope, "all")).toBe(true);
+    expect(isSettingsSearchScopeAvailable(fallback.scope, "project")).toBe(false);
     const streaming = getSettingsSearchTargetScope("response-streaming")!;
     expect(streaming.scope).toBe("project-defaults");
     expect(isSettingsSearchScopeAvailable(streaming.scope, "project")).toBe(true);

apps/web/src/components/settings/settingsSearch.ts

@@ -276,6 +276,14 @@ export const SETTINGS_SEARCH_ITEMS = [
     scope: "project-defaults",
     searchTerms: ["new thread project provider reasoning effort"],
   },
+  {
+    id: "fallback-model",
+    title: "Fallback model",
+    to: "/settings/threads",
+    scope: "environment-defaults",
+    searchTerms: ["fallback agent provider out of usage new threads"],
+    environmentOnly: true,
+  },
   {
     id: "default-permissions",
     title: "Permissions",