vent_agent_2.0/agents/openai_compat.py

"""自定义 OpenAI 兼容网关的请求格式适配。"""

from __future__ import annotations

from typing import Any

from langchain_core.language_models import LanguageModelInput
from langchain_openai import ChatOpenAI


class GatewayChatOpenAI(ChatOpenAI):
    """保留工具调用信息，同时兼容不接受 assistant.content=null 的网关。"""

    def _get_request_payload(
        self,
        input_: LanguageModelInput,
        *,
        stop: list[str] | None = None,
        **kwargs: Any,
    ) -> dict:
        payload = super()._get_request_payload(input_, stop=stop, **kwargs)
        # LangChain 将空的工具调用消息序列化为 content=null；现场网关仅接受
        # str 或 list，因此首次调用正常，回传工具结果的下一轮请求却返回 422。
        # 只改发送时的字典，不修改会话消息、检查点或工具名/参数/调用 ID。
        for message in payload.get("messages", []):
            if (
                message.get("role") == "assistant"
                and message.get("tool_calls")
                and message.get("content") is None
            ):
                message["content"] = ""
        return payload