diff --git a/apps/ai-game-creator-shell/src/App.tsx b/apps/ai-game-creator-shell/src/App.tsx
index b1e65d5fc..703ebcaf7 100644
--- a/apps/ai-game-creator-shell/src/App.tsx
+++ b/apps/ai-game-creator-shell/src/App.tsx
@@ -787,6 +787,17 @@ export function App({
     useState(false);
   const queuedChatTurnSequenceRef = useRef(0);
   const chatComposerRef = useRef<ResourceReferenceInputHandle | null>(null);
+  /**
+   * 切项目即清空只属于上一个项目的输入盒状态：待发附件的 `localPath` 是**项目相对**的，
+   * 队列也属于刚结束的那条对话；留着会把 A 项目的附件路径带进 B 项目的下一个回合。
+   */
+  useEffect(() => {
+    setChatAttachments([]);
+    setChatAttachmentNotice('');
+    setChatComposerNotice('');
+    setChatTurnQueue([]);
+    chatTurnQueueRef.current = [];
+  }, [localProject?.projectPath]);
   const [chatAgentBusy, setChatAgentBusy] = useState(false);
   const [directCodexProgress, setDirectCodexProgress] = useState('');
   const [directCodexStatus, setDirectCodexStatus] = useState<