diff --git a/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
index 885d8cc33..62b408736 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
@@ -6566,7 +6566,32 @@ export function registerProjectWorkbenchFoundationTests() {
           };
         }
         if (command === 'ensure_ui_design_resource_for_prototype') {
-          return null;
+          // 必须返回真实形状的成功结果：返回 `null` 会让 `result.manifest.projectId`
+          // 抛 TypeError 并被组件吞进错误分支，用例就永远测不到它名字里的成功路径。
+          return {
+            asset: {
+              id: 'ui-design-doc',
+              kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+              mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
+              localPath: 'assets/ui-design.json',
+              source: { kind: 'generated' as const },
+            },
+            manifest: {
+              ...manifest,
+              assets: [
+                ...manifest.assets,
+                {
+                  id: 'ui-design-doc',
+                  kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+                  mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
+                  localPath: 'assets/ui-design.json',
+                  source: { kind: 'generated' as const },
+                },
+              ],
+            },
+            committedProjectRevision: 1,
+            created: true,
+          };
         }
         throw new Error(`unexpected invoke ${command}`);
       },
@@ -6599,6 +6624,15 @@ export function registerProjectWorkbenchFoundationTests() {
         }),
       }),
     );
+    // 成功路径：桥接结果被接受后画布切到 UI 编辑器视图；走错误分支时会停在
+    // `resources.selected.*` 并在提示条上留下原因，这条断言让用例真的覆盖它名字里的事。
+    await waitFor(() =>
+      expect(
+        screen
+          .getByLabelText('项目主视窗')
+          .getAttribute('data-resource-view-state'),
+      ).toBe('resources.ui-editor'),
+    );
   });
 
   it('refuses to embed a non-loopback game preview in the client workbench', () => {