diff --git a/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx b/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx
index 825c7e98d..c26b260bf 100644
--- a/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx
+++ b/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx
@@ -35,10 +35,16 @@ import {
   captureClientError,
   installWebviewLogBridge,
 } from '../services/errorReporting';
+import type { AuthNetworkFailure } from '../services/generated/AuthNetworkFailure';
+import type { AuthResponseInvalid } from '../services/generated/AuthResponseInvalid';
+import type { AuthServiceUnavailable } from '../services/generated/AuthServiceUnavailable';
+import type { ClientSessionPersistFailed } from '../services/generated/ClientSessionPersistFailed';
 import type { PasswordLoginRejected } from '../services/generated/PasswordLoginRejected';
 import type { PhoneCodeLoginRejected } from '../services/generated/PhoneCodeLoginRejected';
+import type { RuntimeSessionInstallFailed } from '../services/generated/RuntimeSessionInstallFailed';
 import type { SendCodeRejected } from '../services/generated/SendCodeRejected';
 import type { ServerAddressRejected } from '../services/generated/ServerAddressRejected';
+import type { UnexpectedRejection } from '../services/generated/UnexpectedRejection';
 import {
   beginPlatformSessionClearTransition,
   beginPlatformSessionTransition,
@@ -269,7 +275,13 @@ export function AuthenticatedClient({
         if (!isActiveRun()) return;
         // 失败一律先离开检查态：系统变体虽然要原样抛出上报，界面也不能卡在 loading。
         setAuthStatus('unauthenticated');
-        if (!(error instanceof ClientAuthErrorWrapper)) throw error;
+        // 启动检查超时等我们自己的失败：改动前会显示原因 + 重试按钮，这里恢复同样的可见反馈。
+        if (!(error instanceof ClientAuthErrorWrapper)) {
+          const text = error instanceof Error ? error.message : String(error);
+          setAuthCheckError(text);
+          setLoginStatus(text);
+          throw error;
+        }
         const failure = error.error;
         switch (failure.type) {
           // 预期业务拒绝：调用方补上本次操作的上下文，展示后不进错误池。
@@ -368,15 +380,83 @@ export function AuthenticatedClient({
           case 'sessionInvalidated':
           case 'permissionDenied':
             break;
-          // 系统失败：调用方处理不了，原样抛出 → 全局 unhandledrejection 交给错误池。
-          case 'authNetworkFailure':
-          case 'authServiceUnavailable':
-          case 'unexpectedRejection':
-          case 'authResponseInvalid':
-          case 'clientSessionPersistFailed':
-          case 'runtimeSessionInstallFailed':
-          case 'authClientInitFailed':
+          // 系统失败：调用方处理不了，先按原始事实给用户可见反馈，再原样抛出 → 全局 unhandledrejection 交给错误池。
+          case 'authNetworkFailure': {
+            const payload = failure as AuthNetworkFailure;
+            const text =
+              payload.reason === 'timeout'
+                ? '登录服务响应超时，请检查服务器地址和网络后重试'
+                : '无法连接登录服务，请确认配套后端或 API 代理已启动后重试';
+            setAuthCheckError(text);
+            setLoginStatus(text);
             throw error;
+          }
+          case 'authServiceUnavailable': {
+            const payload = failure as AuthServiceUnavailable;
+            const text = `登录服务暂时不可用（HTTP ${payload.status}）`;
+            setAuthCheckError(text);
+            setLoginStatus(text);
+            throw error;
+          }
+          case 'unexpectedRejection': {
+            const payload = failure as UnexpectedRejection;
+            const text = payload.serverMessage
+              ? `登录服务请求失败（HTTP ${payload.status}）：${payload.serverMessage}`
+              : `登录服务请求失败（HTTP ${payload.status}）`;
+            setAuthCheckError(text);
+            setLoginStatus(text);
+            throw error;
+          }
+          case 'authResponseInvalid': {
+            const payload = failure as AuthResponseInvalid;
+            let text: string;
+            switch (payload.reason) {
+              case 'notJson':
+                text = '登录服务响应不是合法 JSON';
+                break;
+              case 'invalidBody':
+                text = '登录服务响应结构不符合契约';
+                break;
+              case 'missingRefreshCookie':
+                text = '登录服务未返回新的续期凭据';
+                break;
+              case 'missingUserIdentity':
+                text = '登录服务未返回用户身份';
+                break;
+              case 'serverRejected':
+                text = payload.serverMessage
+                  ? `登录服务拒绝了本次请求：${payload.serverMessage}`
+                  : '登录服务拒绝了本次请求';
+                break;
+              default: {
+                expectNever(payload.reason);
+                text = '登录服务响应不符合契约';
+              }
+            }
+            setAuthCheckError(text);
+            setLoginStatus(text);
+            throw error;
+          }
+          case 'clientSessionPersistFailed': {
+            const payload = failure as ClientSessionPersistFailed;
+            const text = `本机登录凭据读写失败：${payload.detail}`;
+            setAuthCheckError(text);
+            setLoginStatus(text);
+            throw error;
+          }
+          case 'runtimeSessionInstallFailed': {
+            const payload = failure as RuntimeSessionInstallFailed;
+            const text = `本机运行时会话安装失败：${payload.detail}`;
+            setAuthCheckError(text);
+            setLoginStatus(text);
+            throw error;
+          }
+          case 'authClientInitFailed': {
+            const text = '创建登录网络客户端失败';
+            setAuthCheckError(text);
+            setLoginStatus(text);
+            throw error;
+          }
           default: {
             expectNever(failure);
             throw error;
diff --git a/apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts
index 0fad9ed16..9ead2250f 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts
@@ -127,9 +127,15 @@ export function registerAuthTests() {
           ).toBe(true),
         { timeout: 20_000 },
       );
+      // 启动检查失败在改动前就会显示原因 + 重试按钮；上报是叠加的，不是替换。
+      expect(
+        await screen.findByText(
+          '检查登录状态超时，请检查服务器地址和网络后重试',
+        ),
+      ).not.toBeNull();
       expect(
         screen.queryByRole('button', { name: '重试登录状态检查' }),
-      ).toBeNull();
+      ).not.toBeNull();
       await screen.findByRole('main', { name: '登录' });
     } finally {
       window.removeEventListener('unhandledrejection', onRejection);