diff --git a/apps/ai-game-creator-shell/src/App.tsx b/apps/ai-game-creator-shell/src/App.tsx
index 014217e10..ec6f00905 100644
--- a/apps/ai-game-creator-shell/src/App.tsx
+++ b/apps/ai-game-creator-shell/src/App.tsx
@@ -584,13 +584,15 @@ export function App({
   onMakeGameFromApprovedGdd,
 }: AppProps = {}) {
   const { setTitle: setWindowTitle } = useWindowChrome();
-  const [planningV2Active, setPlanningV2Active] = useState(planningStartMode);
-  const planningV2ActiveRef = useRef(planningStartMode);
+  const [planningV2Active, setPlanningV2Active] = useState(false);
+  const planningV2ActiveRef = useRef(false);
+  const [designAgentActive, setDesignAgentActive] = useState(planningStartMode);
+  const designAgentActiveRef = useRef(planningStartMode);
   planningV2ActiveRef.current = planningV2Active;
+  designAgentActiveRef.current = designAgentActive;
   const [designAgentView, setDesignAgentView] = useState<DesignView | null>(
     null,
   );
-  const designAgentLaneRef = useRef(planningStartMode);
   const designAgentTurnRef = useRef<{
     projectPath: string;
     clientTurnId: string;
@@ -609,7 +611,9 @@ export function App({
     projectSupervisorOnly &&
     !supervisorChatOnly &&
     !planningStartMode &&
-    !planningV2Active;
+    !planningV2Active &&
+    !designAgentActive;
+  const planningLaneActive = planningV2Active || designAgentActive;
   const [devMode] = useState(() =>
     projectSupervisorOnly ? false : isDeveloperMode(),
   );
@@ -826,12 +830,16 @@ export function App({
     useState('');
   const planningV2TransientReplyTargetRef = useRef('');
   const planningV2VisibleReplyRef = useRef('');
+  const [designAgentTransientReply, setDesignAgentTransientReplyVisible] =
+    useState('');
+  const designAgentTransientReplyTargetRef = useRef('');
+  const designAgentVisibleReplyRef = useRef('');
   const designAgentPendingViewRef = useRef<{
     clientTurnId: string;
     projectPath: string;
     view: DesignView;
   } | null>(null);
-  const [planningV2Reasoning, setPlanningV2Reasoning] = useState('');
+  const [designAgentReasoning, setDesignAgentReasoning] = useState('');
   const designAgentReasoningTurnRef = useRef<{
     projectPath: string;
     clientTurnId: string;
@@ -864,6 +872,14 @@ export function App({
     }
   }
 
+  function setDesignAgentTransientReplyTarget(next: string) {
+    designAgentTransientReplyTargetRef.current = next;
+    if (!next) {
+      designAgentVisibleReplyRef.current = '';
+      setDesignAgentTransientReplyVisible('');
+    }
+  }
+
   function designAgentEventSubscriptionReady() {
     // 业务动作只读取当前订阅代次；清理与下一次 effect 建立之间不能创建
     // 一个没有订阅 effect 接管的悬挂 promise。
@@ -909,12 +925,37 @@ export function App({
     return () => window.clearInterval(timer);
   }, []);
 
+  useEffect(() => {
+    const timer = window.setInterval(() => {
+      const target = designAgentTransientReplyTargetRef.current;
+      setDesignAgentTransientReplyVisible((current) => {
+        if (!target) {
+          designAgentVisibleReplyRef.current = '';
+          return '';
+        }
+        const prefix = target.startsWith(current) ? current : '';
+        if (prefix === target) {
+          designAgentVisibleReplyRef.current = target;
+          return target;
+        }
+        const remaining = target.length - prefix.length;
+        const step = remaining > 160 ? 4 : remaining > 48 ? 2 : 1;
+        const next = target.slice(0, prefix.length + step);
+        designAgentVisibleReplyRef.current = next;
+        return next;
+      });
+    }, 50);
+    return () => window.clearInterval(timer);
+  }, []);
+
   function applyPlanningV2CommandResult(
     result: PlanningSessionCommandResultV2,
     clientTurnId?: string,
   ) {
     planningV2ActiveRef.current = true;
     setPlanningV2Active(true);
+    designAgentActiveRef.current = false;
+    setDesignAgentActive(false);
     planningV2SessionRef.current = result;
     setPlanningV2Session(result);
     projectSupervisorSessionIdRef.current = result.session.sessionId;
@@ -1004,13 +1045,15 @@ export function App({
       setPlanningV2Session(null);
       setPlanGddState(null);
       if (planningStartMode) {
-        planningV2ActiveRef.current = true;
-        setPlanningV2Active(true);
-        designAgentLaneRef.current = true;
+        planningV2ActiveRef.current = false;
+        setPlanningV2Active(false);
+        designAgentActiveRef.current = true;
+        setDesignAgentActive(true);
       }
       return null;
     }
-    designAgentLaneRef.current = false;
+    designAgentActiveRef.current = false;
+    setDesignAgentActive(false);
     setDesignAgentView(null);
     applyPlanningV2CommandResult(result);
     return result;
@@ -1039,10 +1082,9 @@ export function App({
   }
 
   function applyDesignView(view: DesignView, projectPath: string) {
-    designAgentLaneRef.current = true;
+    designAgentActiveRef.current = true;
+    setDesignAgentActive(true);
     setDesignAgentView(view);
-    planningV2ActiveRef.current = true;
-    setPlanningV2Active(true);
     setPlanGddError(view.session.lastError);
     setChatAgentBusy(view.running);
     const conversation = designMessagesToChat(view);
@@ -1056,8 +1098,8 @@ export function App({
     const pendingTurnId = designAgentPendingViewRef.current?.clientTurnId;
     designAgentPendingViewRef.current = null;
     applyDesignView(view, projectPath);
-    setPlanningV2Reasoning('');
-    setPlanningV2TransientReplyTarget('');
+    setDesignAgentReasoning('');
+    setDesignAgentTransientReplyTarget('');
     if (designAgentTurnRef.current?.clientTurnId === pendingTurnId) {
       designAgentTurnRef.current = null;
     }
@@ -1068,7 +1110,7 @@ export function App({
     projectPath: string,
     clientTurnId: string,
   ) {
-    let target = planningV2TransientReplyTargetRef.current;
+    let target = designAgentTransientReplyTargetRef.current;
     const tracked = designAgentTurnRef.current;
     if (!target.trim() && !view.running) {
       const latestAssistantText = [...view.messages]
@@ -1076,7 +1118,7 @@ export function App({
         .find((message) => message.role !== 'user' && message.text.trim())
         ?.text.trim();
       if (latestAssistantText) {
-        setPlanningV2TransientReplyTarget(latestAssistantText);
+        setDesignAgentTransientReplyTarget(latestAssistantText);
         target = latestAssistantText;
       }
     }
@@ -1084,7 +1126,7 @@ export function App({
       !view.running &&
       tracked?.clientTurnId === clientTurnId &&
       target.trim() &&
-      planningV2VisibleReplyRef.current !== target
+      designAgentVisibleReplyRef.current !== target
     ) {
       designAgentPendingViewRef.current = {
         clientTurnId,
@@ -1102,8 +1144,8 @@ export function App({
       if (!pending) {
         return;
       }
-      const target = planningV2TransientReplyTargetRef.current;
-      if (target && planningV2VisibleReplyRef.current !== target) {
+      const target = designAgentTransientReplyTargetRef.current;
+      if (target && designAgentVisibleReplyRef.current !== target) {
         return;
       }
       commitDesignAgentView(pending.view, pending.projectPath);
@@ -1155,8 +1197,8 @@ export function App({
     await designAgentEventSubscriptionReady();
     setChatAgentBusy(true);
     setProjectSupervisorRuntimeError('');
-    setPlanningV2TransientReplyTarget('');
-    setPlanningV2Reasoning('');
+    setDesignAgentTransientReplyTarget('');
+    setDesignAgentReasoning('');
     try {
       const view = await invoke<DesignView>('continue_design_agent_session', {
         projectPath: nextProjectPath,
@@ -1180,7 +1222,7 @@ export function App({
     } finally {
       if (!designAgentPendingViewRef.current) {
         designAgentTurnRef.current = null;
-        setPlanningV2TransientReplyTarget('');
+        setDesignAgentTransientReplyTarget('');
       }
       setChatAgentBusy(false);
     }
@@ -1642,10 +1684,11 @@ export function App({
     setPlanningV2TransientReplyTarget('');
     designAgentPendingViewRef.current = null;
     designAgentReasoningTurnRef.current = null;
-    setPlanningV2Reasoning('');
-    setPlanningV2Active(planningStartMode);
-    planningV2ActiveRef.current = planningStartMode;
-    designAgentLaneRef.current = planningStartMode;
+    setDesignAgentReasoning('');
+    setPlanningV2Active(false);
+    planningV2ActiveRef.current = false;
+    setDesignAgentActive(planningStartMode);
+    designAgentActiveRef.current = planningStartMode;
     designAgentTurnRef.current = null;
     setDesignAgentView(null);
   }
@@ -1912,7 +1955,7 @@ export function App({
     if (
       !canSubscribeTauriEvents() ||
       directCodexProductRuntime ||
-      planningV2Active
+      planningLaneActive
     ) {
       return;
     }
@@ -2015,7 +2058,7 @@ export function App({
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [
     directCodexProductRuntime,
-    planningV2Active,
+    planningLaneActive,
     refreshManifest,
     updateProjectSupervisorResponseStream,
     updateProjectSupervisorRuntime,
@@ -2023,7 +2066,7 @@ export function App({
 
   useEffect(() => {
     const ready = createDesignAgentEventSubscriptionReady();
-    if (!canSubscribeTauriEvents() || !planningV2Active) {
+    if (!canSubscribeTauriEvents() || !designAgentActive) {
       resolveDesignAgentEventSubscriptionReady();
       return () => {
         if (designAgentEventSubscriptionReadyRef.current === ready) {
@@ -2044,7 +2087,7 @@ export function App({
         return;
       }
       if (payload.kind === 'text' && payload.text != null) {
-        setPlanningV2TransientReplyTarget(payload.text);
+        setDesignAgentTransientReplyTarget(payload.text);
       }
       if (payload.reasoningText != null) {
         const reasoningTurn = designAgentReasoningTurnRef.current;
@@ -2054,11 +2097,11 @@ export function App({
           reasoningTurn.clientTurnId === payload.clientTurnId
         ) {
           reasoningTurn.text = payload.reasoningText;
-          setPlanningV2Reasoning(payload.reasoningText);
+          setDesignAgentReasoning(payload.reasoningText);
         }
       }
       if (payload.kind === 'tool' && payload.text) {
-        setPlanningV2TransientReplyTarget(payload.text);
+        setDesignAgentTransientReplyTarget(payload.text);
       }
       if (payload.view) {
         applyDesignAgentViewAfterTransient(
@@ -2091,7 +2134,7 @@ export function App({
     // applyDesignView 读的是 refs 和当前项目路径，
     // 把它写进依赖会在每轮回复时重订事件。
     // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [planningV2Active]);
+  }, [designAgentActive]);
 
   useEffect(() => {
     if (!canSubscribeTauriEvents()) {
@@ -2140,7 +2183,7 @@ export function App({
     if (
       !invoke ||
       directCodexProductRuntime ||
-      planningV2Active ||
+      planningLaneActive ||
       !nextProjectPath ||
       !sessionId ||
       !trackedRunId ||
@@ -2236,7 +2279,7 @@ export function App({
   }, [
     localProject?.projectPath,
     directCodexProductRuntime,
-    planningV2Active,
+    planningLaneActive,
     projectSupervisorSessionId,
     projectSupervisorRuntime?.phase,
     projectSupervisorRuntime?.runId,
@@ -2251,7 +2294,7 @@ export function App({
     if (
       !projectSupervisorOnly ||
       directCodexProductRuntime ||
-      planningV2Active ||
+      planningLaneActive ||
       !invoke ||
       !nextProjectPath ||
       !supervisorRunId
@@ -2332,7 +2375,7 @@ export function App({
   }, [
     localProject?.projectPath,
     directCodexProductRuntime,
-    planningV2Active,
+    planningLaneActive,
     projectSupervisorOnly,
     projectSupervisorRuntime?.phase,
     projectSupervisorRuntime?.runId,
@@ -2344,7 +2387,7 @@ export function App({
       (!supervisorChatOnly &&
         !(
           projectSupervisorOnly &&
-          (directCodexProductRuntime || planningV2Active)
+          (directCodexProductRuntime || planningLaneActive)
         )) ||
       !supervisorChatShouldFollowLatestRef.current
     ) {
@@ -2364,7 +2407,7 @@ export function App({
     directCodexTransientReply,
     directCodexTransientReplyUpdatedAt,
     directCodexProductRuntime,
-    planningV2Active,
+    planningLaneActive,
     projectSupervisorOnly,
     supervisorChatOnly,
   ]);
@@ -3333,14 +3376,16 @@ export function App({
         ) {
           return;
         }
-        planningV2ActiveRef.current = true;
-        setPlanningV2Active(true);
+        planningV2ActiveRef.current = Boolean(planningV2);
+        setPlanningV2Active(Boolean(planningV2));
         if (planningV2) {
-          designAgentLaneRef.current = false;
+          designAgentActiveRef.current = false;
+          setDesignAgentActive(false);
           setDesignAgentView(null);
           applyPlanningV2CommandResult(planningV2);
         } else {
-          designAgentLaneRef.current = true;
+          designAgentActiveRef.current = true;
+          setDesignAgentActive(true);
           planningV2SessionRef.current = null;
           setPlanningV2Session(null);
           setPlanGddState(null);
@@ -6138,7 +6183,6 @@ export function App({
     setChatAgentBusy(true);
     setProjectSupervisorRuntimeError('');
     setPlanningV2TransientReplyTarget('');
-    setPlanningV2Reasoning('');
     try {
       const result = currentSessionId
         ? await invoke<PlanningSessionCommandResultV2>(
@@ -6204,13 +6248,17 @@ export function App({
     directPolicyChecked = false,
     references,
   }: ExecuteChatAgentReplyInput) {
-    if (planningV2ActiveRef.current || planningStartMode) {
+    if (
+      planningV2ActiveRef.current ||
+      designAgentActiveRef.current ||
+      planningStartMode
+    ) {
       const nextProjectPath = resolveChatProjectPath(localProject);
       if (!nextProjectPath) {
         setProjectSupervisorRuntimeError('请先初始化本地项目');
         return;
       }
-      if (designAgentLaneRef.current) {
+      if (designAgentActiveRef.current) {
         await executeDesignAgentTurn(
           nextProjectPath,
           { type: 'message', text: prompt },
@@ -7074,7 +7122,7 @@ export function App({
     answers: Record<string, string>,
   ) {
     const nextProjectPath = resolveChatProjectPath(localProject);
-    if (planningV2ActiveRef.current || planningStartMode) {
+    if (planningV2ActiveRef.current) {
       const current = planningV2SessionRef.current;
       const currentQuestion = current?.session.currentQuestion;
       const answer = Object.values(answers)
@@ -11774,7 +11822,7 @@ export function App({
       (agent.runtimeStatus !== null || agent.hasRecentEvidence),
   );
   const useDesignAgentSurface =
-    Boolean(designAgentView) || (planningStartMode && !planningV2Session);
+    Boolean(designAgentView) || (designAgentActive && !planningV2Session);
 
   if (projectSupervisorOnly && supervisorChatOnly) {
     const supervisorProjectPath =
@@ -11807,11 +11855,13 @@ export function App({
         runtimeConfigOpen={runtimeConfigOpen}
         runtimeError={projectSupervisorRuntimeError}
         transientReply={
-          planningV2Active
-            ? planningV2TransientReply
-            : directCodexProductRuntime
-              ? directCodexTransientReply
-              : projectSupervisorTransientReply
+          designAgentActive
+            ? designAgentTransientReply
+            : planningV2Active
+              ? planningV2TransientReply
+              : directCodexProductRuntime
+                ? directCodexTransientReply
+                : projectSupervisorTransientReply
         }
         hasConversationControls={projectSupervisorHasConversationControls}
         hiddenConversationCount={hiddenConversationCount}
@@ -11857,14 +11907,16 @@ export function App({
         pendingCommand={directCodexProductRuntime ? pendingCommand : null}
         projectPath={localProject?.projectPath ?? projectPath}
         transientReply={
-          planningV2Active
-            ? planningV2TransientReply
-            : directCodexProductRuntime
-              ? directCodexTransientReply
-              : projectSupervisorTransientReply
+          designAgentActive
+            ? designAgentTransientReply
+            : planningV2Active
+              ? planningV2TransientReply
+              : directCodexProductRuntime
+                ? directCodexTransientReply
+                : projectSupervisorTransientReply
         }
-        showDesignReasoning={planningV2Active}
-        designReasoning={planningV2Reasoning}
+        showDesignReasoning={designAgentActive}
+        designReasoning={designAgentReasoning}
         designReasoningEntries={
           useDesignAgentSurface ? (designAgentView?.reasoningEntries ?? []) : []
         }
@@ -11880,7 +11932,7 @@ export function App({
         planGddError={planGddError}
         onPlanGddRefresh={() => void hydratePlanGddState()}
         onPlanGddDecision={decidePlanGdd}
-        planningLane={planningV2Active}
+        planningLane={planningLaneActive}
         designView={useDesignAgentSurface ? designAgentView : null}
         onDesignApprove={
           useDesignAgentSurface
@@ -11901,8 +11953,8 @@ export function App({
                   text: '',
                 };
                 designAgentPendingViewRef.current = null;
-                setPlanningV2TransientReplyTarget('');
-                setPlanningV2Reasoning('');
+                setDesignAgentTransientReplyTarget('');
+                setDesignAgentReasoning('');
                 setChatAgentBusy(true);
                 setPlanGddDecisionBusy(true);
                 void designAgentEventSubscriptionReady()
@@ -11951,7 +12003,7 @@ export function App({
                     }
                     if (!designAgentPendingViewRef.current) {
                       designAgentTurnRef.current = null;
-                      setPlanningV2TransientReplyTarget('');
+                      setDesignAgentTransientReplyTarget('');
                     }
                     setChatAgentBusy(false);
                     setPlanGddDecisionBusy(false);