fix agent tool call history ordering

app/agent/middleware/patch_tool_calls.py

@@ -1,7 +1,7 @@
-from typing import Any
+from typing import Any, Optional
 
 from langchain.agents.middleware import AgentMiddleware, AgentState
-from langchain_core.messages import AIMessage, ToolMessage
+from langchain_core.messages import AIMessage, BaseMessage, ToolMessage
 from langgraph.runtime import Runtime
 from langgraph.types import Overwrite
 
@@ -9,35 +9,65 @@ from langgraph.types import Overwrite
 class PatchToolCallsMiddleware(AgentMiddleware):
     """修复消息历史中悬空工具调用的中间件。"""
 
-    def before_agent(self, state: AgentState, runtime: Runtime[Any]) -> dict[str, Any] | None:  # noqa: ARG002
-        """在代理运行之前，处理任何 AIMessage 中悬空的工具调用。"""
-        messages = state["messages"]
+    @staticmethod
+    def _build_cancelled_tool_message(tool_call: dict[str, Any]) -> ToolMessage:
+        """构造取消状态的工具响应消息。"""
+        tool_name = tool_call.get("name") or "unknown_tool"
+        tool_call_id = tool_call.get("id") or ""
+        tool_msg = (
+            f"Tool call {tool_name} with id {tool_call_id} was "
+            "cancelled - another message came in before it could be completed."
+        )
+        return ToolMessage(
+            content=tool_msg,
+            name=tool_name,
+            tool_call_id=tool_call_id,
+        )
+
+    @classmethod
+    def _normalize_messages(cls, messages: list[BaseMessage]) -> list[BaseMessage]:
+        """规范化工具调用消息顺序，满足 OpenAI tool_calls 协议要求。"""
         if not messages or len(messages) == 0:
+            return messages
+
+        tool_messages = {
+            msg.tool_call_id: msg
+            for msg in messages
+            if isinstance(msg, ToolMessage) and msg.tool_call_id
+        }
+        patched_messages = []
+        for msg in messages:
+            if isinstance(msg, ToolMessage):
+                continue
+
+            patched_messages.append(msg)
+            if not isinstance(msg, AIMessage) or not msg.tool_calls:
+                continue
+
+            for tool_call in msg.tool_calls:
+                tool_call_id = tool_call.get("id")
+                corresponding_tool_msg = tool_messages.get(tool_call_id)
+                if corresponding_tool_msg:
+                    patched_messages.append(corresponding_tool_msg)
+                else:
+                    patched_messages.append(cls._build_cancelled_tool_message(tool_call))
+
+        return patched_messages
+
+    def before_agent(self, state: AgentState, runtime: Runtime[Any]) -> Optional[dict[str, Any]]:  # noqa: ARG002
+        """在代理运行之前，处理任何 AIMessage 中悬空或乱序的工具调用。"""
+        messages = state["messages"]
+        patched_messages = self._normalize_messages(messages)
+        if patched_messages == messages:
             return None
 
-        patched_messages = []
-        # 遍历消息并添加任何悬空的工具调用
-        for i, msg in enumerate(messages):
-            patched_messages.append(msg)
-            if isinstance(msg, AIMessage) and msg.tool_calls:
-                for tool_call in msg.tool_calls:
-                    corresponding_tool_msg = next(
-                        (msg for msg in messages[i:] if msg.type == "tool" and msg.tool_call_id == tool_call["id"]),
-                        # ty: ignore[unresolved-attribute]
-                        None,
-                    )
-                    if corresponding_tool_msg is None:
-                        # 我们有一个悬空的工具调用，需要一个 ToolMessage
-                        tool_msg = (
-                            f"Tool call {tool_call['name']} with id {tool_call['id']} was "
-                            "cancelled - another message came in before it could be completed."
-                        )
-                        patched_messages.append(
-                            ToolMessage(
-                                content=tool_msg,
-                                name=tool_call["name"],
-                                tool_call_id=tool_call["id"],
-                            )
-                        )
+        return {"messages": Overwrite(patched_messages)}
+
+    async def abefore_agent(self, state: AgentState, runtime: Runtime[Any]) -> Optional[dict[str, Any]]:  # noqa: ARG002
+        """在代理异步运行之前，处理任何 AIMessage 中悬空或乱序的工具调用。"""
+        messages = state["messages"]
+        patched_messages = self._normalize_messages(messages)
+        if patched_messages == messages:
+            return None
 
         return {"messages": Overwrite(patched_messages)}