fix: tool_calls 流中断自愈——400 配对错误时移除不完整段重试一次；加消息结构诊断日志

web/agent_api.py

@@ -367,6 +367,16 @@ def _agent_thread(run_id, prompt, serial, cfg):
                 _log.warning(f"经验保存异常: {e}")
     except Exception as e:
         _log.warning(f"Agent 运行异常: {e}")
+        # 诊断：打印消息结构（tool_calls 与 tool 消息配对检查）
+        try:
+            roles = [m.get("role", "?") for m in agent.messages]
+            tcs = sum(1 for m in agent.messages
+                      if m.get("tool_calls") and isinstance(m.get("tool_calls"), list))
+            tools_msg = sum(1 for m in agent.messages if m.get("role") == "tool")
+            _log.warning(f"诊断 messages: {len(agent.messages)} 条 roles={roles[-8:]} "
+                         f"tool_calls消息={tcs} tool回应={tools_msg}")
+        except Exception:
+            pass
         with _lock:
             _run["state"] = "error"
             _run["error"] = f"{type(e).__name__}: {str(e)[:200]}"