diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs
index 14c1e9ec7..7c6f2d4db 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs
@@ -845,6 +845,26 @@ pub(crate) fn hydrate_design_agent_session(
     Ok(Some(design_view(&session, active.is_none())))
 }
 
+#[tauri::command]
+pub(crate) fn get_design_agent_runtime_mode(
+    project_path: String,
+) -> Result<Option<DesignRuntimeMode>, String> {
+    let root = Path::new(project_path.trim());
+    enforce_project_permission_policy(root, "conversation.read")?;
+    design_project_id(root)?;
+    resolve_design_runtime_mode(root)
+}
+
+fn resolve_design_runtime_mode(root: &Path) -> Result<Option<DesignRuntimeMode>, String> {
+    if let Some(mode) = read_design_runtime_mode(root)? {
+        return Ok(Some(mode));
+    }
+    // 已有策划会话可能早于运行模式文件；明确的 game 标记始终优先。
+    Ok(read_design_session(root)?.map(|_| DesignRuntimeMode {
+        active_runtime: "design".into(),
+    }))
+}
+
 #[tauri::command]
 pub(crate) fn set_design_agent_runtime_mode(
     project_path: String,
@@ -1054,6 +1074,37 @@ mod fake_provider {
 mod tests {
     use super::*;
 
+    #[test]
+    fn runtime_mode_restore_prefers_explicit_mode_over_existing_design_session() {
+        let temporary = tempfile::tempdir().expect("tempdir");
+        let root = temporary.path();
+        assert_eq!(resolve_design_runtime_mode(root).unwrap(), None);
+        write_design_session(root, &new_design_session("project", "")).unwrap();
+        assert_eq!(
+            resolve_design_runtime_mode(root)
+                .unwrap()
+                .unwrap()
+                .active_runtime,
+            "design"
+        );
+        write_design_runtime_mode(root, "game").unwrap();
+        assert_eq!(
+            resolve_design_runtime_mode(root)
+                .unwrap()
+                .unwrap()
+                .active_runtime,
+            "game"
+        );
+        write_design_runtime_mode(root, "design").unwrap();
+        assert_eq!(
+            resolve_design_runtime_mode(root)
+                .unwrap()
+                .unwrap()
+                .active_runtime,
+            "design"
+        );
+    }
+
     #[test]
     fn design_runtime_rejects_design_execution_in_game_mode() {
         let temporary = tempfile::tempdir().expect("create runtime mode root");
diff --git a/apps/ai-game-creator-shell/src-tauri/src/main.rs b/apps/ai-game-creator-shell/src-tauri/src/main.rs
index 3c93f0697..5be012475 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/main.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/main.rs
@@ -2583,6 +2583,7 @@ fn main() {
             decide_planning_artifact_v2,
             hydrate_planning_session_v2,
             hydrate_design_agent_session,
+            get_design_agent_runtime_mode,
             set_design_agent_runtime_mode,
             debug_fast_forward_design_session,
             continue_design_agent_session,
diff --git a/apps/ai-game-creator-shell/src/features/app-shell/useHomeProjectCreation.ts b/apps/ai-game-creator-shell/src/features/app-shell/useHomeProjectCreation.ts
index 1ab395f17..849d56ceb 100644
--- a/apps/ai-game-creator-shell/src/features/app-shell/useHomeProjectCreation.ts
+++ b/apps/ai-game-creator-shell/src/features/app-shell/useHomeProjectCreation.ts
@@ -252,6 +252,12 @@ export function useHomeProjectCreation({
     attachments: HomeAttachmentDraft[],
     startMode: ProjectStartMode,
   ) {
+    if (startMode === 'planning') {
+      await invoke('set_design_agent_runtime_mode', {
+        projectPath: result.projectPath,
+        activeRuntime: 'design',
+      });
+    }
     const importedAttachments = await importHomeAttachments(
       invoke,
       result.projectPath,
@@ -477,6 +483,11 @@ export function useHomeProjectCreation({
         setStatus('这不是已初始化的 AI 游戏项目，请使用新建项目。');
         return;
       }
+      const runtimeMode = await invoke<{
+        activeRuntime: 'design' | 'game';
+      } | null>('get_design_agent_runtime_mode', {
+        projectPath: trimmedProjectPath,
+      });
       setStatus('已打开项目');
       enterProjectDevelopment({
         projectPath: trimmedProjectPath,
@@ -494,7 +505,7 @@ export function useHomeProjectCreation({
           trimmedProjectPath,
         ),
         creationType: null,
-        startMode: null,
+        startMode: runtimeMode?.activeRuntime === 'design' ? 'planning' : null,
         initialPrompt: '',
         attachments: [],
         recentRunStatus: directoryStatus.recentRunStatus,
diff --git a/apps/ai-game-creator-shell/src/features/project-workspace/DesignWorkspacePanel.tsx b/apps/ai-game-creator-shell/src/features/project-workspace/DesignWorkspacePanel.tsx
index d8a894b9b..932208819 100644
--- a/apps/ai-game-creator-shell/src/features/project-workspace/DesignWorkspacePanel.tsx
+++ b/apps/ai-game-creator-shell/src/features/project-workspace/DesignWorkspacePanel.tsx
@@ -186,6 +186,7 @@ export function DesignWorkspacePanel({
     () => new Set(),
   );
   const refreshTimerRef = useRef<number | null>(null);
+  const refreshHydrateSessionRef = useRef(false);
 
   const loadWorkspace = useCallback(
     async ({
@@ -266,20 +267,27 @@ export function DesignWorkspacePanel({
     }
     let disposed = false;
     let cleanup: (() => void) | null = null;
-    const scheduleRefresh = () => {
+    const scheduleRefresh = (hydrateSession: boolean) => {
+      refreshHydrateSessionRef.current =
+        refreshHydrateSessionRef.current || hydrateSession;
       if (refreshTimerRef.current !== null) {
         window.clearTimeout(refreshTimerRef.current);
       }
       refreshTimerRef.current = window.setTimeout(() => {
         refreshTimerRef.current = null;
-        void loadWorkspace({ showLoading: false, hydrateSession: false });
+        const shouldHydrateSession = refreshHydrateSessionRef.current;
+        refreshHydrateSessionRef.current = false;
+        void loadWorkspace({
+          showLoading: false,
+          hydrateSession: shouldHydrateSession,
+        });
       }, 250);
     };
     void listen<{ projectPath: string; kind: string }>(
       'design-agent-update',
       (event) => {
         if (!disposed && event.payload.projectPath === projectPath) {
-          scheduleRefresh();
+          scheduleRefresh(event.payload.kind === 'state');
         }
       },
     )
@@ -297,6 +305,7 @@ export function DesignWorkspacePanel({
         window.clearTimeout(refreshTimerRef.current);
         refreshTimerRef.current = null;
       }
+      refreshHydrateSessionRef.current = false;
       cleanup?.();
     };
   }, [loadWorkspace, projectPath]);
diff --git a/apps/ai-game-creator-shell/tests/appSurface/harness.ts b/apps/ai-game-creator-shell/tests/appSurface/harness.ts
index ab4939de2..0d0cf0a10 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/harness.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/harness.ts
@@ -853,6 +853,12 @@ function createProjectSupervisorRuntimeHarness({
       if (command === 'hydrate_design_agent_session') {
         return currentDesignAgentView;
       }
+      if (command === 'get_design_agent_runtime_mode') {
+        return currentDesignAgentView ? { activeRuntime: 'design' } : null;
+      }
+      if (command === 'set_design_agent_runtime_mode') {
+        return { activeRuntime: args?.activeRuntime };
+      }
       if (command === 'continue_design_agent_session') {
         const next = currentDesignContinueView ?? currentDesignAgentView;
         if (!next) {
diff --git a/apps/ai-game-creator-shell/tests/appSurface/home.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/home.suite.ts
index 53d3dc5c4..9da80a84d 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/home.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/home.suite.ts
@@ -222,6 +222,7 @@ export function registerClientHomeTests() {
     }
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -368,6 +369,7 @@ export function registerClientHomeTests() {
     let manifestChanged = false;
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -537,6 +539,7 @@ export function registerClientHomeTests() {
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
         const requestedPath = String(args?.projectPath ?? '');
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath: requestedPath,
@@ -714,6 +717,7 @@ export function registerClientHomeTests() {
       });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath: String(args?.projectPath ?? ''),
@@ -1176,6 +1180,7 @@ export function registerHomeProjectCreationTests() {
     let inspectCount = 0;
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           inspectCount += 1;
           return {
@@ -1241,6 +1246,7 @@ export function registerHomeProjectCreationTests() {
   it('does not open a missing or non-directory path from the open action', async () => {
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           const projectPath = String(args?.projectPath ?? '');
           if (projectPath === '/tmp/broken-status') {
@@ -1338,6 +1344,7 @@ export function registerHomeProjectCreationTests() {
           expect(args).toBeUndefined();
           return '/tmp/picked-game';
         }
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath: '/tmp/picked-game',
@@ -1368,6 +1375,7 @@ export function registerHomeProjectCreationTests() {
       if (command === 'pick_local_project_directory') {
         return '/tmp/broken-project';
       }
+      if (command === 'get_design_agent_runtime_mode') return null;
       if (command === 'inspect_local_project_directory') {
         return {
           projectPath: '/tmp/broken-project',
@@ -2459,6 +2467,7 @@ export function registerRecentProjectsTests() {
     ];
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           const projectPath = String(args?.projectPath ?? '');
           if (projectPath === paths[0]) {
@@ -2605,6 +2614,7 @@ export function registerRecentProjectsTests() {
     );
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           const renamed =
             invoke.mock.calls.filter(
@@ -2659,6 +2669,7 @@ export function registerRecentProjectsTests() {
     const projectPath = '/tmp/rename-failed-game';
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -2705,6 +2716,7 @@ export function registerRecentProjectsTests() {
   it('opens a recent launcher project directory in the system file manager', async () => {
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath: String(args?.projectPath ?? ''),
@@ -2758,6 +2770,7 @@ export function registerRecentProjectsTests() {
 
   it('does not remember a launcher project when project inspection fails', async () => {
     const invoke = vi.fn(async (command: string) => {
+      if (command === 'get_design_agent_runtime_mode') return null;
       if (command === 'inspect_local_project_directory') {
         throw new Error('inspect failed');
       }
@@ -2775,6 +2788,7 @@ export function registerRecentProjectsTests() {
   it('marks missing recent launcher projects and does not reopen them', async () => {
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           const projectPath = String(args?.projectPath ?? '');
           if (projectPath === '/tmp/broken-status') {
@@ -2919,6 +2933,7 @@ export function registerRecentProjectsTests() {
   it('checks recent launcher project status automatically without changing the list', async () => {
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           const projectPath = String(args?.projectPath ?? '');
           return {
@@ -2977,6 +2992,7 @@ export function registerRecentProjectsTests() {
         }) => void)
       | null = null;
     const invoke = vi.fn(async (command: string) => {
+      if (command === 'get_design_agent_runtime_mode') return null;
       if (command === 'inspect_local_project_directory') {
         return await new Promise((resolve) => {
           finishRefresh = resolve;
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 e92aab6d7..8de960f80 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
@@ -4749,6 +4749,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -4869,6 +4870,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -4933,6 +4935,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -5007,6 +5010,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -5108,6 +5112,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -5543,6 +5548,7 @@ export function registerProjectSupervisorSurfaceTests() {
     );
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -6031,6 +6037,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -6108,6 +6115,7 @@ export function registerProjectSupervisorSurfaceTests() {
     });
     const invoke = vi.fn(
       async (command: string, args?: Record<string, unknown>) => {
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
@@ -6182,6 +6190,7 @@ export function registerProjectSupervisorSurfaceTests() {
         if (command === 'pick_local_project_directory') {
           return projectPath;
         }
+        if (command === 'get_design_agent_runtime_mode') return null;
         if (command === 'inspect_local_project_directory') {
           return {
             projectPath,
diff --git a/apps/ai-game-creator-shell/tests/designProjectRestore.test.tsx b/apps/ai-game-creator-shell/tests/designProjectRestore.test.tsx
new file mode 100644
index 000000000..11181ccc0
--- /dev/null
+++ b/apps/ai-game-creator-shell/tests/designProjectRestore.test.tsx
@@ -0,0 +1,82 @@
+// @vitest-environment jsdom
+import { act, cleanup, renderHook } from '@testing-library/react';
+import { afterEach, expect, it, vi } from 'vitest';
+
+import { createGameCreationAppManifest } from '../../../packages/shared/src/contracts/gameCreationApp';
+import { useHomeProjectCreation } from '../src/features/app-shell/useHomeProjectCreation';
+
+afterEach(() => {
+  cleanup();
+  delete window.__TAURI__;
+});
+
+const projectPath = 'C:/test/design-project';
+const manifest = createGameCreationAppManifest('test-project', '策划项目');
+
+function setup(invoke: ReturnType<typeof vi.fn>) {
+  window.__TAURI__ = { core: { invoke } } as unknown as typeof window.__TAURI__;
+  return renderHook(() =>
+    useHomeProjectCreation({
+      setStatus: vi.fn(),
+      setLauncherView: vi.fn(),
+      setAgentChatProjectPath: vi.fn(),
+      rememberRecentWorkspace: vi.fn(),
+    }),
+  );
+}
+
+it.each(['design', 'game', null] as const)(
+  'restores %s before publishing the project context',
+  async (mode) => {
+    let resolveMode!: (value: { activeRuntime: string } | null) => void;
+    const modePromise = new Promise<{ activeRuntime: string } | null>(
+      (resolve) => {
+        resolveMode = resolve;
+      },
+    );
+    const invoke = vi.fn(async (command: string) => {
+      if (command === 'inspect_local_project_directory')
+        return { exists: true, isDirectory: true, isGameCreatorProject: true };
+      if (command === 'get_local_game_manifest') return manifest;
+      if (command === 'get_local_game_project_revision') return { revision: 1 };
+      if (command === 'get_design_agent_runtime_mode') return modePromise;
+      throw new Error(command);
+    });
+    const { result } = setup(invoke);
+    let opening!: Promise<void>;
+    await act(async () => {
+      opening = result.current.openProject(projectPath, 'open');
+    });
+    expect(result.current.currentProjectContext).toBeNull();
+    await act(async () => {
+      resolveMode(mode ? { activeRuntime: mode } : null);
+      await opening;
+    });
+    expect(result.current.currentProjectContext?.startMode).toBe(
+      mode === 'design' ? 'planning' : null,
+    );
+  },
+);
+
+it('persists design mode before entering a newly created planning project', async () => {
+  const invoke = vi.fn(async (command: string) => {
+    if (command === 'create_automatic_local_game_project')
+      return { projectPath, manifest };
+    if (command === 'set_design_agent_runtime_mode')
+      return { activeRuntime: 'design' };
+    if (command === 'get_local_game_project_revision') return { revision: 1 };
+    throw new Error(command);
+  });
+  const { result } = setup(invoke);
+  await act(async () => {
+    await result.current.createHomeDraftAutomatically(
+      { creationType: 'game', prompt: '测试', attachments: [] },
+      'planning',
+    );
+  });
+  expect(invoke).toHaveBeenCalledWith('set_design_agent_runtime_mode', {
+    projectPath,
+    activeRuntime: 'design',
+  });
+  expect(result.current.currentProjectContext?.startMode).toBe('planning');
+});
diff --git a/docs/project-memory/shared-memory/pitfalls.md b/docs/project-memory/shared-memory/pitfalls.md
index 3004a9902..8ed9581fa 100644
--- a/docs/project-memory/shared-memory/pitfalls.md
+++ b/docs/project-memory/shared-memory/pitfalls.md
@@ -2,6 +2,11 @@
 
 > 当前口径：本文件保留可复用的排障经验；历史条目的旧路由、旧版本和已删除文档仅作根因背景，不得据此恢复退役入口。当前命令、路由和 schema 以代码与 `docs/README.md` 为准。
 
+## 2026-09-12 策划项目重开前必须恢复运行模式
+
+- 工作台不能只依赖创建时的内存 `startMode`：重开时丢失该值会挂载游戏资源画布，而对话恢复后又进入策划状态，造成左右区域不一致。
+- 新建策划项目进入工作台前持久化 `.agent/runtime-mode.json`；重开先读取模式再发布项目上下文。无模式文件的旧项目用策划会话恢复为 design，明确的 game 标记优先于旧会话。
+
 ## 2026-09-10 设计 Agent 需要流式 Responses 的原生 output[]，不能只靠 tool_calls
 
 - **现象**：新策划报 `Provider 返回工具调用但未提供完整 Responses output`。模型已经在调工具，`.debug/design-agent` 里 `tool_calls` 有值但 `output` 是 `[]`。
diff --git a/docs/technical/【技术方案】策划Agent生产迁移与工作区浏览-2026-09-10.md b/docs/technical/【技术方案】策划Agent生产迁移与工作区浏览-2026-09-10.md
index b47357753..4d0bc94fe 100644
--- a/docs/technical/【技术方案】策划Agent生产迁移与工作区浏览-2026-09-10.md
+++ b/docs/technical/【技术方案】策划Agent生产迁移与工作区浏览-2026-09-10.md
@@ -342,6 +342,8 @@ UI 使用“批准”和“继续修改”两个文字按钮，分别配 Lucide
 
 ## 14. 开发调试入口
 
+项目运行模式通过 `.agent/runtime-mode.json` 持久化。新建策划项目在进入工作台前写入 `design`；“做成游戏”写入 `game`。重新打开项目时通过 `get_design_agent_runtime_mode` 读取模式，完成后一次性挂载对应工作台，不能先挂载 GameAgent 再切回策划。旧项目缺少模式文件但存在策划会话时按 `design` 恢复；明确的 `game` 标记优先于残留策划会话。无模式也无策划会话的项目仍使用游戏工作台。
+
 开发构建的策划工作区页头在“刷新”旁提供“快速准备做成游戏测试”按钮。该入口与策划 Debug 日志共用 `GENARRATIVE_AGC_DESIGN_DEBUG=1` 开关：开关未启用时按钮不显示，命令也不可执行。入口仅进行本地 fixture 和会话状态写入，不调用 Provider；完成后自动刷新文件树与阶段，通过 `design-agent-update` 状态事件同步右侧审批/阶段操作区。随后仍需点击正常的“做成游戏”按钮执行资产登记与运行时切换。
 
 ## 15. 策划 Agent reasoning 展示现状