feat(settings): pre-keys keyless login for desktop passkey Sync sign-in

packages/fxa-settings/src/lib/hooks/useFxAStatus/index.test.tsx

@@ -120,7 +120,7 @@ describe('useFxAStatus', () => {
         });
       });
 
-      it('returns supportsKeysOptionalLogin: true when Relay or SmartWindow service', async () => {
+      it('reports browserSupportsKeysOptional: true when the browser advertises keys_optional', async () => {
         const integration = {
           type: IntegrationType.OAuthNative,
           isSync: () => false,
@@ -131,10 +131,13 @@ describe('useFxAStatus', () => {
         );
 
         await waitForNextUpdate();
-        expect(result.current.supportsKeysOptionalLogin).toBe(true);
+        expect(result.current.browserSupportsKeysOptional).toBe(true);
       });
 
-      it('returns supportsKeysOptionalLogin: false for Sync', async () => {
+      // The hook reports the raw browser capability regardless of integration
+      // type; whether a Sync login may use it is decided on the integration
+      // model (see Integration.supportsKeylessLogin), not here.
+      it('reports browserSupportsKeysOptional: true for Sync when the browser advertises it', async () => {
         const integration = {
           type: IntegrationType.OAuthNative,
           isSync: () => true,
@@ -144,7 +147,23 @@ describe('useFxAStatus', () => {
           useFxAStatus(integration)
         );
         await waitForNextUpdate();
-        expect(result.current.supportsKeysOptionalLogin).toBe(false);
+        expect(result.current.browserSupportsKeysOptional).toBe(true);
+      });
+
+      it('reports browserSupportsKeysOptional: false when the browser omits keys_optional', async () => {
+        (firefox.fxaStatus as jest.Mock).mockResolvedValue({
+          capabilities: { engines: [] },
+        });
+        const integration = {
+          type: IntegrationType.OAuthNative,
+          isSync: () => false,
+          isFirefoxNonSync: () => true,
+        };
+        const { result, waitForNextUpdate } = renderHook(() =>
+          useFxAStatus(integration)
+        );
+        await waitForNextUpdate();
+        expect(result.current.browserSupportsKeysOptional).toBe(false);
       });
     });
   });

packages/fxa-settings/src/lib/hooks/useFxAStatus/index.tsx

@@ -41,8 +41,10 @@ export function useFxAStatus(integration: FxAStatusIntegration) {
     typeof syncEngineConfigs | undefined
   >();
   const [declinedSyncEngines, setDeclinedSyncEngines] = useState<string[]>([]);
-  const [supportsKeysOptionalLogin, setSupportsKeysOptionalLogin] =
-    useState<boolean>(false);
+  // Raw browser `keys_optional` capability. Per-integration policy (whether a
+  // given login may skip keys) lives on the Integration model, not here.
+  const [browserSupportsKeysOptional, setBrowserSupportsKeysOptional] =
+    useState(false);
   const [supportsCanLinkAccountUid, setSupportsCanLinkAccountUid] = useState<
     boolean | undefined
   >(undefined);
@@ -77,17 +79,9 @@ export function useFxAStatus(integration: FxAStatusIntegration) {
             setWebChannelEngines(capabilities.engines);
           }
         }
-        // Check if third party auth (passwordless) log in to the browser is supported,
-        // currently only Firefox desktop 147+ as of Q1 2026
-        if (
-          capabilities.keys_optional &&
-          isOAuthNative &&
-          integration.isFirefoxNonSync()
-        ) {
-          setSupportsKeysOptionalLogin(true);
-        } else {
-          setSupportsKeysOptionalLogin(false);
-        }
+        // Report the raw browser `keys_optional` capability (Fx desktop 147+ as
+        // of Q1 2026). Consumers decide per-integration whether it applies.
+        setBrowserSupportsKeysOptional(!!capabilities.keys_optional);
         if (capabilities.can_link_account_uid) {
           setSupportsCanLinkAccountUid(true);
         } else {
@@ -154,7 +148,7 @@ export function useFxAStatus(integration: FxAStatusIntegration) {
     offeredSyncEngineConfigs,
     declinedSyncEngines,
     selectedEnginesForGlean,
-    supportsKeysOptionalLogin,
+    browserSupportsKeysOptional,
     supportsCanLinkAccountUid,
   };
 }

packages/fxa-settings/src/lib/hooks/useFxAStatus/mocks.tsx

@@ -7,11 +7,11 @@ import type { UseFxAStatusResult } from '.';
 
 export function mockUseFxAStatus({
   offeredSyncEnginesOverride,
-  supportsKeysOptionalLogin = false,
+  browserSupportsKeysOptional = false,
   supportsCanLinkAccountUid,
 }: {
   offeredSyncEnginesOverride?: ReturnType<typeof getSyncEngineIds>;
-  supportsKeysOptionalLogin?: boolean;
+  browserSupportsKeysOptional?: boolean;
   supportsCanLinkAccountUid?: boolean | undefined;
 } = {}) {
   const offeredSyncEngineConfigs = syncEngineConfigs;
@@ -35,7 +35,7 @@ export function mockUseFxAStatus({
     offeredSyncEngineConfigs,
     declinedSyncEngines,
     selectedEnginesForGlean,
-    supportsKeysOptionalLogin,
+    browserSupportsKeysOptional,
     supportsCanLinkAccountUid,
   } satisfies UseFxAStatusResult;
 }