diff --git a/src/AutoAgent/AutoAgent.cpp b/src/AutoAgent/AutoAgent.cpp
index a284ba7..abae7bc 100644
--- a/src/AutoAgent/AutoAgent.cpp
+++ b/src/AutoAgent/AutoAgent.cpp
@@ -50,7 +50,7 @@ extern "C" AcRx::AppRetCode acrxEntryPoint(AcRx::AppMsgCode msg, void* pkt)
 void CR_SCGXCmdFnc();
 void InitApplication()
 {
-	mcp::close_mcp();
+	mcp::init_mcp();
 
 	acrxBuildClassHierarchy();
 	AddCommand(_T("SHCRACKTOOLS"), _T("CR_SCGX"), _T("CR_SCGX"), ACRX_CMD_TRANSPARENT | ACRX_CMD_USEPICKSET, CR_SCGXCmdFnc);
diff --git a/src/AutoAgent/mcp.cpp b/src/AutoAgent/mcp.cpp
index 4612b6f..a23829b 100644
--- a/src/AutoAgent/mcp.cpp
+++ b/src/AutoAgent/mcp.cpp
@@ -8,20 +8,24 @@
 
 #pragma comment(lib, "ws2_32.lib")
 
+#define WM_MCP_EXECUTE_TASK (WM_USER + 2048)
+
 static std::thread g_serverThread;
 static std::atomic<bool> g_bRunning(false);
 static SOCKET g_listenSocket = INVALID_SOCKET;
 
+static HWND g_hMsgWnd = NULL;
+static const wchar_t* g_szMsgClassName = L"AutoAgentMcpMsgWndClass";
+
 // 用于跨线程传递数据的结构体
 struct TaskData
 {
 	std::string rawJson;
 };
 
-// 真正执行绘图的回调函数 (此函数由 AutoCAD 主线程调度运行)
-static void MainThreadCallback(void *pData)
+// 此函数在 AutoCAD 主 UI 线程运行，绝对安全.
+void ExecuteTaskInMainThread(TaskData *pTask)
 {
-	TaskData *pTask = static_cast<TaskData *>(pData);
 	if (pTask == nullptr)
 	{
 		return;
@@ -29,7 +33,6 @@ static void MainThreadCallback(void *pData)
 
 	try
 	{
-		// 1. 解析 JSON 指令
 		auto j = nlohmann::json::parse(pTask->rawJson);
 		if (j.contains("cmd") && j["cmd"] == "draw_circle")
 		{
@@ -37,43 +40,57 @@ static void MainThreadCallback(void *pData)
 			double y = j.value("y", 0.0);
 			double r = j.value("r", 100.0);
 
-			// 2. 锁定当前活动文档 (跨线程操作后的绝对必要步骤)
 			AcApDocument *pDoc = acDocManager->curDocument();
 			if (pDoc)
 			{
-				acDocManager->lockDocument(pDoc, AcAp::kWrite, nullptr, nullptr, false);
+				// 此时在主线程，安全锁文档
+				Acad::ErrorStatus es = acDocManager->lockDocument(pDoc, AcAp::kWrite, nullptr, nullptr, false);
+				if (es == Acad::eOk)
+				{
+					AcDbDatabase *pDb = pDoc->database();
+					AcDbBlockTable *pBlockTable = nullptr;
+					pDb->getBlockTable(pBlockTable, AcDb::kForRead);
 
-				// 3. 常规 ObjectARX 绘图逻辑
-				AcDbDatabase *pDb = pDoc->database();
-				AcDbBlockTable *pBlockTable = nullptr;
-				pDb->getBlockTable(pBlockTable, AcDb::kForRead);
+					AcDbBlockTableRecord *pBTR = nullptr;
+					pBlockTable->getAt(ACDB_MODEL_SPACE, pBTR, AcDb::kForWrite);
+					pBlockTable->close();
 
-				AcDbBlockTableRecord *pBTR = nullptr;
-				pBlockTable->getAt(ACDB_MODEL_SPACE, pBTR, AcDb::kForWrite);
-				pBlockTable->close();
+					AcGePoint3d center(x, y, 0.0);
+					AcGeVector3d normal(0.0, 0.0, 1.0);
+					AcDbCircle *pCircle = new AcDbCircle(center, normal, r);
 
-				AcGePoint3d center(x, y, 0.0);
-				AcGeVector3d normal(0.0, 0.0, 1.0);
-				AcDbCircle *pCircle = new AcDbCircle(center, normal, r);
+					AcDbObjectId circleId;
+					pBTR->appendAcDbEntity(circleId, pCircle);
 
-				AcDbObjectId circleId;
-				pBTR->appendAcDbEntity(circleId, pCircle);
+					pBTR->close();
+					pCircle->close();
 
-				pBTR->close();
-				pCircle->close();
-
-				acDocManager->unlockDocument(pDoc);
-				acutPrintf(_T("\n[MCP Server] 成功在坐标(%.2f, %.2f)绘制了半径为%.2f的圆\n"), x, y, r);
+					acDocManager->unlockDocument(pDoc);
+					acutPrintf(_T("\n[MCP Server] 成功在坐标(%.2f, %.2f)绘制了半径为%.2f的圆\n"), x, y, r);
+				}
 			}
 		}
 	}
 	catch (...)
 	{
-		acutPrintf(_T("\n[MCP Server] JSON 解析或执行异常!\n"));
+		acutPrintf(_T("\n[MCP Server] JSON 解析或绘图异常!\n"));
 	}
+}
 
-	// 4. 清理由 Socket 线程在堆上分配的内存
-	delete pTask;
+// 隐式窗口的回调函数 (属于主线程)
+LRESULT CALLBACK McpWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
+{
+	if (message == WM_MCP_EXECUTE_TASK)
+	{
+		TaskData *pTask = reinterpret_cast<TaskData *>(lParam);
+		if (pTask)
+		{
+			ExecuteTaskInMainThread(pTask);
+			delete pTask; // 执行完毕，清理内存
+		}
+		return 0;
+	}
+	return DefWindowProc(hWnd, message, wParam, lParam);
 }
 
 // TCP 监听后台线程
@@ -114,8 +131,15 @@ static void TcpServerLoop()
 					TaskData *pTask = new TaskData;
 					pTask->rawJson = recvBuf;
 
-					// 核心：委托 AutoCAD 主线程在下一个消息循环中执行回调
-					acDocManager->executeInApplicationContext(MainThreadCallback, pTask);
+					// 关键转变：通过 PostMessage 发送给主线程拥有的隐式窗口
+					if (g_hMsgWnd != NULL)
+					{
+						PostMessage(g_hMsgWnd, WM_MCP_EXECUTE_TASK, 0, reinterpret_cast<LPARAM>(pTask));
+					}
+					else
+					{
+						delete pTask;
+					}
 				}
 				closesocket(clientSocket);
 			}
@@ -130,6 +154,24 @@ namespace mcp
 {
 	bool init_mcp()
 	{
+		// 1. 在主线程注册并创建 Message-Only 窗口
+		WNDCLASSEX wc = { 0 };
+		wc.cbSize = sizeof(WNDCLASSEX);
+		wc.lpfnWndProc = McpWndProc;
+		wc.hInstance = GetModuleHandle(NULL);
+		wc.lpszClassName = g_szMsgClassName;
+		RegisterClassEx(&wc);
+
+		g_hMsgWnd = CreateWindowEx(
+			0,
+			g_szMsgClassName,
+			L"AutoAgentMcpMsgWindow",
+			0, 0, 0, 0, 0,
+			HWND_MESSAGE, // 纯消息窗口，无界面、无感知
+			NULL,
+			GetModuleHandle(NULL),
+			NULL
+		);
 		g_bRunning = true;
 		try
 		{
@@ -153,6 +195,14 @@ namespace mcp
 		{
 			g_serverThread.join();
 		}
+
+		if (g_hMsgWnd != NULL)
+		{
+			DestroyWindow(g_hMsgWnd);
+			UnregisterClass(g_szMsgClassName, GetModuleHandle(NULL));
+			g_hMsgWnd = NULL;
+		}
+
 		acutPrintf(_T("\n[MCP Server] 插件已卸载，线程已关闭。\n"));
 		return true;
 	}