diff --git a/apps/ai-game-creator-shell/src/App.tsx b/apps/ai-game-creator-shell/src/App.tsx
index fc4bee85b..87683987d 100644
--- a/apps/ai-game-creator-shell/src/App.tsx
+++ b/apps/ai-game-creator-shell/src/App.tsx
@@ -833,6 +833,11 @@ export function App({
     view: DesignView;
   } | null>(null);
   const [planningV2Reasoning, setPlanningV2Reasoning] = useState('');
+  const designAgentReasoningTurnRef = useRef<{
+    projectPath: string;
+    clientTurnId: string;
+    text: string;
+  } | null>(null);
   const planningV2TurnRef = useRef<{
     projectPath: string;
     clientTurnId: string;
@@ -1125,6 +1130,11 @@ export function App({
       projectPath: nextProjectPath,
       clientTurnId,
     };
+    designAgentReasoningTurnRef.current = {
+      projectPath: nextProjectPath,
+      clientTurnId,
+      text: '',
+    };
     designAgentPendingViewRef.current = null;
     await designAgentEventSubscriptionReady();
     setChatAgentBusy(true);
@@ -1648,6 +1658,7 @@ export function App({
     setPlanningV2Session(null);
     setPlanningV2TransientReplyTarget('');
     designAgentPendingViewRef.current = null;
+    designAgentReasoningTurnRef.current = null;
     setPlanningV2Reasoning('');
     setPlanningV2Active(planningStartMode);
     planningV2ActiveRef.current = planningStartMode;
@@ -2108,7 +2119,15 @@ export function App({
         setPlanningV2TransientReplyTarget(payload.text);
       }
       if (payload.reasoningText != null) {
-        setPlanningV2Reasoning(payload.reasoningText);
+        const reasoningTurn = designAgentReasoningTurnRef.current;
+        if (
+          reasoningTurn &&
+          reasoningTurn.projectPath === payload.projectPath &&
+          reasoningTurn.clientTurnId === payload.clientTurnId
+        ) {
+          reasoningTurn.text = payload.reasoningText;
+          setPlanningV2Reasoning(payload.reasoningText);
+        }
       }
       if (payload.kind === 'tool' && payload.text) {
         setPlanningV2TransientReplyTarget(payload.text);
@@ -11936,6 +11955,11 @@ export function App({
                   projectPath: nextProjectPath,
                   clientTurnId,
                 };
+                designAgentReasoningTurnRef.current = {
+                  projectPath: nextProjectPath,
+                  clientTurnId,
+                  text: '',
+                };
                 designAgentPendingViewRef.current = null;
                 setPlanningV2TransientReplyTarget('');
                 setPlanningV2Reasoning('');
diff --git a/apps/ai-game-creator-shell/src/features/project-workspace/ProjectSupervisorView.tsx b/apps/ai-game-creator-shell/src/features/project-workspace/ProjectSupervisorView.tsx
index ef8a6b119..f111ac332 100644
--- a/apps/ai-game-creator-shell/src/features/project-workspace/ProjectSupervisorView.tsx
+++ b/apps/ai-game-creator-shell/src/features/project-workspace/ProjectSupervisorView.tsx
@@ -263,8 +263,11 @@ export function ProjectSupervisorView({
             </div>
           ))}
           {designReasoning ? (
-            <details className="design-agent-reasoning">
-              <summary>显示思考过程</summary>
+            <details
+              className="design-agent-reasoning"
+              aria-label="策划 Agent 思考过程"
+            >
+              <summary>思考过程（点击展开）</summary>
               <pre>{designReasoning}</pre>
             </details>
           ) : null}
diff --git a/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts
index 5fa401401..3160d8756 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/design-agent.suite.ts
@@ -7,6 +7,7 @@ import {
   React,
   render,
   screen,
+  setComposerText,
   waitFor,
 } from './harness';
 
@@ -55,6 +56,24 @@ function designClarificationView() {
   };
 }
 
+function designConversationView() {
+  return {
+    session: {
+      sessionId: 'design-session-reasoning',
+      projectId: 'local-project-draft',
+      currentPhase: 'concept',
+      approvedPhases: [],
+      pendingApproval: null,
+      pendingClarification: null,
+      turnIndex: 1,
+      lastError: null,
+    },
+    messages: [],
+    running: false,
+    canRetry: false,
+  };
+}
+
 export function registerDesignAgentSurfaceTests() {
   it('hydrates an existing design session and decides approval through design commands', async () => {
     const harness = createProjectSupervisorRuntimeHarness({
@@ -141,4 +160,54 @@ export function registerDesignAgentSurfaceTests() {
       ).toBe(true);
     });
   });
+
+  it('keeps the current turn reasoning after completion and supports collapse/expand', async () => {
+    const harness = createProjectSupervisorRuntimeHarness({
+      designAgentView: designConversationView(),
+      designAgentContinueView: designConversationView(),
+    });
+    window.__TAURI__ = {
+      core: { invoke: harness.invoke },
+      event: { listen: harness.listen },
+    };
+    window.history.pushState({}, '', '/');
+    render(
+      React.createElement(App, {
+        initialProjectPath: harness.projectPath,
+        orchestrationMode: 'single-supervisor',
+        planningStartMode: true,
+        projectSupervisorOnly: true,
+      }),
+    );
+
+    const input = await screen.findByLabelText('项目需求');
+    await setComposerText(input, '请给出核心玩法方案');
+    fireEvent.submit(input.closest('form') as HTMLFormElement);
+    await waitFor(() => {
+      expect(
+        harness.invoke.mock.calls.some(
+          ([command]) => command === 'continue_design_agent_session',
+        ),
+      ).toBe(true);
+    });
+    const continueCall = [...harness.invoke.mock.calls]
+      .reverse()
+      .find(([command]) => command === 'continue_design_agent_session');
+    const clientTurnId = String(
+      (continueCall?.[1] as { clientTurnId?: string }).clientTurnId,
+    );
+    harness.emitDesignAgentEvent({
+      projectPath: harness.projectPath,
+      clientTurnId,
+      kind: 'reasoning',
+      reasoningText: '先分析需求，再组织方案。',
+    });
+
+    const summary = await screen.findByText('思考过程（点击展开）');
+    const details = summary.closest('details') as HTMLDetailsElement;
+    expect(details.open).toBe(false);
+    fireEvent.click(summary);
+    expect(details.open).toBe(true);
+    expect(screen.getByText('先分析需求，再组织方案。')).not.toBeNull();
+  });
 }
diff --git a/apps/ai-game-creator-shell/tests/appSurface/harness.ts b/apps/ai-game-creator-shell/tests/appSurface/harness.ts
index 3c6da89f6..2400ea259 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/harness.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/harness.ts
@@ -741,6 +741,9 @@ function createProjectSupervisorRuntimeHarness({
         };
       }) => void)
     | null = null;
+  let designAgentUpdateHandler:
+    | ((event: { payload: Record<string, unknown> }) => void)
+    | null = null;
 
   const conversationRecord = (
     role: 'user' | 'assistant',
@@ -1113,6 +1116,10 @@ function createProjectSupervisorRuntimeHarness({
       if (eventName === 'game-creator-agent-progress') {
         progressHandler = handler as unknown as typeof progressHandler;
       }
+      if (eventName === 'design-agent-update') {
+        designAgentUpdateHandler =
+          handler as unknown as typeof designAgentUpdateHandler;
+      }
       return () => {
         if (runtimeUpdateHandler === handler) {
           runtimeUpdateHandler = null;
@@ -1123,6 +1130,9 @@ function createProjectSupervisorRuntimeHarness({
         if (progressHandler === handler) {
           progressHandler = null;
         }
+        if (designAgentUpdateHandler === handler) {
+          designAgentUpdateHandler = null;
+        }
       };
     },
   );
@@ -1149,6 +1159,9 @@ function createProjectSupervisorRuntimeHarness({
     setPlanningV2Result(state: Record<string, unknown> | null) {
       currentPlanningV2Result = state;
     },
+    emitDesignAgentEvent(payload: Record<string, unknown>) {
+      designAgentUpdateHandler?.({ payload });
+    },
     setPlanningV2StartResult(state: Record<string, unknown> | null) {
       currentPlanningV2StartResult = state;
     },
diff --git a/docs/project-memory/plans/【里程碑】Provider推理与正文分离及策划Agent展示-2026-09-14.md b/docs/project-memory/plans/【里程碑】Provider推理与正文分离及策划Agent展示-2026-09-14.md
index 44322109d..dc122b85c 100644
--- a/docs/project-memory/plans/【里程碑】Provider推理与正文分离及策划Agent展示-2026-09-14.md
+++ b/docs/project-memory/plans/【里程碑】Provider推理与正文分离及策划Agent展示-2026-09-14.md
@@ -3,7 +3,7 @@
 | 字段 | 值 |
 | --- | --- |
 | Version | 1.0 |
-| Status | awaiting-review |
+| Status | in-progress |
 | Date | 2026-09-14 |
 | Parent Spec | `docs/technical/【技术方案】策划Agent生产迁移与工作区浏览-2026-09-10.md` |
 | Related Issue | `GenarrativeAI/Genarrative#331` |
@@ -12,6 +12,12 @@
 
 让策划 Agent 能在流式回合中单独收到 Provider reasoning，并在 UI 中以默认折叠的思考过程展示；用户可见正文、工具调用和 GameAgent 现有行为保持不变。
 
+## 当前实现进度（2026-09-14）
+
+- 已完成共享 reasoning 字段、Provider 解析、策划事件映射以及正文流式收尾的前两轮提交。
+- 当前第三轮聚焦策划 Agent 前端 reasoning 生命周期：按 `projectPath + clientTurnId` 绑定事件，回合结束后保留本轮 reasoning，下一轮或项目切换时清理。
+- 现有 `<details>` 展示保持默认收起，并提供明确的展开/收起入口；不新增持久化字段，也不改动 GameAgent、Direct/Codex、supervisor 或已退役链路。
+
 ## 背景与现状
 
 - `platform-llm` 当前只向上层提供正文累计值、正文增量和结束状态。