diff --git a/pipeline_service/agent_loop_v2.py b/pipeline_service/agent_loop_v2.py
index 3bde1e9..be1a251 100644
--- a/pipeline_service/agent_loop_v2.py
+++ b/pipeline_service/agent_loop_v2.py
@@ -185,7 +185,8 @@ class AgentExecutor:
                     }, ensure_ascii=False) + "\n"
 
                     result = await self._execute_tool(tool_name, tool_params)
-                    self._tool_call_count += 1
+                    if not result.startswith("未知工具"):
+                        self._tool_call_count += 1
 
                     yield json.dumps({
                         "type": "tool_result", "tool": tool_name,