diff --git a/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx b/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx
index c26b260bf..a35b82a5d 100644
--- a/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx
+++ b/apps/ai-game-creator-shell/src/app/AuthenticatedClient.tsx
@@ -554,7 +554,11 @@ export function AuthenticatedClient({
       setCodeCooldownSeconds(Math.max(0, Math.floor(response.cooldownSeconds)));
       setLoginStatus(`验证码已发送，${response.expiresInSeconds} 秒内有效`);
     } catch (error) {
-      if (!(error instanceof ClientAuthErrorWrapper)) throw error;
+      // 本地运行时超时等我们自己的失败也要离开「正在发送验证码」并给出原因，改动前就是如此。
+      if (!(error instanceof ClientAuthErrorWrapper)) {
+        setLoginStatus(error instanceof Error ? error.message : String(error));
+        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。
@@ -644,15 +648,79 @@ export function AuthenticatedClient({
           setLoginStatus('当前账号没有权限执行此操作');
           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;
+          setLoginStatus(
+            payload.reason === 'timeout'
+              ? '发送验证码失败：登录服务响应超时，请检查服务器地址和网络后重试'
+              : '发送验证码失败：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',
+          );
           throw error;
+        }
+        case 'authServiceUnavailable': {
+          const payload = failure as AuthServiceUnavailable;
+          setLoginStatus(
+            `发送验证码失败：登录服务暂时不可用（HTTP ${payload.status}）`,
+          );
+          throw error;
+        }
+        case 'unexpectedRejection': {
+          const payload = failure as UnexpectedRejection;
+          setLoginStatus(
+            payload.serverMessage
+              ? `发送验证码失败：登录服务请求失败（HTTP ${payload.status}）：${payload.serverMessage}`
+              : `发送验证码失败：登录服务请求失败（HTTP ${payload.status}）`,
+          );
+          throw error;
+        }
+        case 'authResponseInvalid': {
+          const payload = failure as AuthResponseInvalid;
+          let text: string;
+          switch (payload.reason) {
+            case 'notJson':
+              text = '发送验证码失败：登录服务响应不是合法 JSON';
+              break;
+            case 'invalidBody':
+              text = '发送验证码失败：登录服务响应结构不符合契约';
+              break;
+            case 'missingRefreshCookie':
+              text = '发送验证码失败：登录服务未返回新的续期凭据';
+              break;
+            case 'missingUserIdentity':
+              text = '发送验证码失败：登录服务未返回用户身份';
+              break;
+            case 'serverRejected':
+              text = payload.serverMessage
+                ? `发送验证码失败：登录服务拒绝了本次请求：${payload.serverMessage}`
+                : '发送验证码失败：登录服务拒绝了本次请求';
+              break;
+            default: {
+              expectNever(payload.reason);
+              text = '发送验证码失败：登录服务响应不符合契约';
+            }
+          }
+          setLoginStatus(text);
+          throw error;
+        }
+        case 'clientSessionPersistFailed': {
+          const payload = failure as ClientSessionPersistFailed;
+          setLoginStatus(
+            `发送验证码失败：本机登录凭据读写失败：${payload.detail}`,
+          );
+          throw error;
+        }
+        case 'runtimeSessionInstallFailed': {
+          const payload = failure as RuntimeSessionInstallFailed;
+          setLoginStatus(
+            `发送验证码失败：本机运行时会话安装失败：${payload.detail}`,
+          );
+          throw error;
+        }
+        case 'authClientInitFailed': {
+          setLoginStatus('发送验证码失败：创建登录网络客户端失败');
+          throw error;
+        }
         default: {
           expectNever(failure);
           throw error;
@@ -722,7 +790,11 @@ export function AuthenticatedClient({
       setCode('');
       setPassword('');
     } catch (error) {
-      if (!(error instanceof ClientAuthErrorWrapper)) throw error;
+      // 本地运行时超时等我们自己的失败也要离开「正在登录」并给出原因，改动前就是如此。
+      if (!(error instanceof ClientAuthErrorWrapper)) {
+        setLoginStatus(error instanceof Error ? error.message : String(error));
+        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。
@@ -812,15 +884,75 @@ export function AuthenticatedClient({
           setLoginStatus('当前账号没有权限执行此操作');
           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;
+          setLoginStatus(
+            payload.reason === 'timeout'
+              ? '登录失败：登录服务响应超时，请检查服务器地址和网络后重试'
+              : '登录失败：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',
+          );
           throw error;
+        }
+        case 'authServiceUnavailable': {
+          const payload = failure as AuthServiceUnavailable;
+          setLoginStatus(
+            `登录失败：登录服务暂时不可用（HTTP ${payload.status}）`,
+          );
+          throw error;
+        }
+        case 'unexpectedRejection': {
+          const payload = failure as UnexpectedRejection;
+          setLoginStatus(
+            payload.serverMessage
+              ? `登录失败：登录服务请求失败（HTTP ${payload.status}）：${payload.serverMessage}`
+              : `登录失败：登录服务请求失败（HTTP ${payload.status}）`,
+          );
+          throw error;
+        }
+        case 'authResponseInvalid': {
+          const payload = failure as AuthResponseInvalid;
+          let text: string;
+          switch (payload.reason) {
+            case 'notJson':
+              text = '登录失败：登录服务响应不是合法 JSON';
+              break;
+            case 'invalidBody':
+              text = '登录失败：登录服务响应结构不符合契约';
+              break;
+            case 'missingRefreshCookie':
+              text = '登录失败：登录服务未返回新的续期凭据';
+              break;
+            case 'missingUserIdentity':
+              text = '登录失败：登录服务未返回用户身份';
+              break;
+            case 'serverRejected':
+              text = payload.serverMessage
+                ? `登录失败：登录服务拒绝了本次请求：${payload.serverMessage}`
+                : '登录失败：登录服务拒绝了本次请求';
+              break;
+            default: {
+              expectNever(payload.reason);
+              text = '登录失败：登录服务响应不符合契约';
+            }
+          }
+          setLoginStatus(text);
+          throw error;
+        }
+        case 'clientSessionPersistFailed': {
+          const payload = failure as ClientSessionPersistFailed;
+          setLoginStatus(`登录失败：本机登录凭据读写失败：${payload.detail}`);
+          throw error;
+        }
+        case 'runtimeSessionInstallFailed': {
+          const payload = failure as RuntimeSessionInstallFailed;
+          setLoginStatus(`登录失败：本机运行时会话安装失败：${payload.detail}`);
+          throw error;
+        }
+        case 'authClientInitFailed': {
+          setLoginStatus('登录失败：创建登录网络客户端失败');
+          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 9ead2250f..b480a0e0c 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts
@@ -281,7 +281,7 @@ export function registerAuthTests() {
     expect(screen.queryByLabelText('已登录')).toBeNull();
   });
 
-  it('keeps transport details out of the login copy by throwing system variants through', async () => {
+  it('shows the system variant copy and still throws it through', async () => {
     const uninstall = installUnhandledRejectionBridge();
     const reasons: unknown[] = [];
     const onRejection = (event: Event) => {
@@ -301,7 +301,7 @@ export function registerAuthTests() {
       renderAuthSurface(invoke);
       await loginWithCode();
 
-      // 先等系统变体真的经 unhandledrejection 抛出，再断言它没落到登录页文案。
+      // 先等系统变体真的经 unhandledrejection 抛出。
       await waitFor(() => expect(reasons).toHaveLength(1));
       // 载体自身 message 留空；诊断信息在 error 字段里，由上报链路取。
       expect(reasons[0]).toBeInstanceOf(ClientAuthErrorWrapper);
@@ -309,7 +309,12 @@ export function registerAuthTests() {
         type: 'authNetworkFailure',
         reason: 'unreachable',
       });
-      expect(screen.queryByText(/无法连接登录服务/u)).toBeNull();
+      // 改动前系统失败也会在登录页给出一行提示；这里恢复同样的可见反馈，只是不泄露传输层细节。
+      expect(
+        await screen.findByText(
+          '登录失败：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',
+        ),
+      ).not.toBeNull();
       expect(document.body.textContent).not.toContain('ECONNREFUSED');
       await screen.findByRole('main', { name: '登录' });
     } finally {