fix(server): Antigravity sign-in no longer blames the network when the runtime never starts

apps/server/src/provider/AntigravityAuth.test.ts

@@ -82,17 +82,21 @@ const makeHarness = Effect.fn("makeAuthTestHarness")(function* (
             yield* Deferred.succeed(closed, undefined);
           }),
         );
+        // Cached like the real AcpSessionRuntime, so start() reuses an earlier initialize.
+        const initialize = yield* Effect.cached(
+          Effect.gen(function* () {
+            events.push("initialize");
+            yield* options.beforeInitialize ?? Effect.void;
+            return options.supportsLogout === false
+              ? { ...initialized, agentCapabilities: {} }
+              : initialized;
+          }),
+        );
         return {
-          initialize: () =>
-            Effect.gen(function* () {
-              events.push("initialize");
-              yield* options.beforeInitialize ?? Effect.void;
-              return options.supportsLogout === false
-                ? { ...initialized, agentCapabilities: {} }
-                : initialized;
-            }),
+          initialize: () => initialize,
           start: () =>
             Effect.gen(function* () {
+              yield* initialize;
               events.push("authenticate");
               yield* Deferred.succeed(authenticateCalled, undefined);
               if (options.interactive !== false && input.onAuthorizationUrl) {
@@ -278,6 +282,35 @@ it.layer(NodeServices.layer)("AntigravityAuth", (it) => {
     }),
   );
 
+  it.effect("does not blame the network when the agent never answers initialize", () =>
+    Effect.gen(function* () {
+      const initializing = yield* Deferred.make<void>();
+      const harness = yield* makeHarness({
+        beforeInitialize: Deferred.succeed(initializing, undefined).pipe(
+          Effect.andThen(Effect.never),
+        ),
+      });
+      yield* harness.auth.controller.start(owner);
+      yield* Deferred.await(initializing);
+      const blamesNetwork = /reach(ed)? Google|network|ipv6/i;
+
+      yield* TestClock.adjust("30 seconds");
+      const stalled = yield* harness.auth.controller.subscribe(owner).pipe(
+        Stream.filter((state) => state.message !== "Starting Google sign-in."),
+        Stream.runHead,
+        Effect.map(Option.getOrThrow),
+      );
+      assert.equal(stalled.phase, "starting");
+      assert.notMatch(stalled.message ?? "", blamesNetwork);
+      assert.match(stalled.message ?? "", /not responded|stuck/i);
+
+      yield* TestClock.adjust("270 seconds");
+      const failed = yield* phase(harness.auth, "failed");
+      assert.notMatch(failed.message ?? "", blamesNetwork);
+      assert.match(failed.message ?? "", /not respond|stuck/i);
+    }),
+  );
+
   it.effect("keeps the expired message once the Google link was shown", () =>
     Effect.gen(function* () {
       const harness = yield* makeHarness();
@@ -383,7 +416,7 @@ it.layer(NodeServices.layer)("AntigravityAuth", (it) => {
       assert.isTrue(Exit.isFailure(competing));
       const resumed = yield* phase(harness.auth, "waiting");
       assert.equal(resumed.flowId, first.flowId);
-      assert.deepEqual(harness.events, ["process-open", "authenticate"]);
+      assert.deepEqual(harness.events, ["process-open", "initialize", "authenticate"]);
       yield* harness.auth.controller.cancel(owner, first.flowId!);
     }),
   );

apps/server/src/provider/AntigravityAuth.ts

@@ -33,7 +33,12 @@ import type { ProviderAuthController } from "./ProviderAuthService.ts";
 const AUTH_TIMEOUT_MS = 300_000;
 // A healthy agent shows the Google link or finishes within seconds. Its bundled Python has no
 // IPv4 fallback race, so a host with broken IPv6 waits about two minutes per Google request.
+// An agent that never answers initialize is hung locally, so the network is not to blame.
 const NO_RESPONSE_HINT_MS = 30_000;
+const NOT_STARTED_MESSAGE =
+  "Antigravity has not responded after 30 seconds. Its runtime may be stuck starting on this machine.";
+const NOT_RESPONDING_MESSAGE =
+  "Antigravity did not respond. Its runtime may not run on this machine.";
 const NO_RESPONSE_MESSAGE =
   "Antigravity has not reached Google after 30 seconds. Check this machine's network connection. Broken IPv6 is a common cause.";
 const UNREACHABLE_MESSAGE =
@@ -53,6 +58,7 @@ interface AuthFlow {
   readonly expiresAtMillis: number;
   state: ProviderAuthState;
   pending: AntigravityAuthorizationUrl | undefined;
+  initialized: boolean;
   callbackSent: boolean;
   fiber: Fiber.Fiber<void> | undefined;
   forwarding: Fiber.Fiber<void, ProviderSetupError> | undefined;
@@ -276,7 +282,10 @@ export const makeAntigravityAuth = Effect.fn("makeAntigravityAuth")(function* <
           lock.withPermits(1)(
             Effect.gen(function* () {
               if (activeFlow !== flow || flow.state.phase !== "starting") return;
-              yield* publishFlow(flow, { ...flow.state, message: NO_RESPONSE_MESSAGE });
+              yield* publishFlow(flow, {
+                ...flow.state,
+                message: flow.initialized ? NO_RESPONSE_MESSAGE : NOT_STARTED_MESSAGE,
+              });
             }),
           ),
         ),
@@ -285,6 +294,8 @@ export const makeAntigravityAuth = Effect.fn("makeAntigravityAuth")(function* <
       const runtime = yield* options.makeRuntime({
         onAuthorizationUrl: (url) => receiveAuthorizationUrl(flow, url),
       });
+      yield* runtime.initialize();
+      flow.initialized = true;
       const started = yield* runtime.start();
       yield* lock.withPermits(1)(
         Effect.gen(function* () {
@@ -309,9 +320,11 @@ export const makeAntigravityAuth = Effect.fn("makeAntigravityAuth")(function* <
             Effect.fail(
               setupError(
                 "start",
-                flow.state.phase === "starting"
-                  ? UNREACHABLE_MESSAGE
-                  : "Google sign-in expired. Start sign-in again.",
+                flow.state.phase !== "starting"
+                  ? "Google sign-in expired. Start sign-in again."
+                  : flow.initialized
+                    ? UNREACHABLE_MESSAGE
+                    : NOT_RESPONDING_MESSAGE,
               ),
             ),
         }),
@@ -398,6 +411,7 @@ export const makeAntigravityAuth = Effect.fn("makeAntigravityAuth")(function* <
               expiresAtMillis,
               state,
               pending: undefined,
+              initialized: false,
               callbackSent: false,
               fiber: undefined,
               forwarding: undefined,