langchain/agents/tools.py

"""Interface for tools."""
from typing import List, Optional

from langchain.callbacks.manager import (
    AsyncCallbackManagerForToolRun,
    CallbackManagerForToolRun,
)
from langchain.tools.base import BaseTool, Tool, tool


class InvalidTool(BaseTool):
    """Tool that is run when invalid tool name is encountered by agent."""

    name: str = "invalid_tool"
    description: str = "Called when tool name is invalid. Suggests valid tool names."

    def _run(
        self,
        requested_tool_name: str,
        available_tool_names: List[str],
        run_manager: Optional[CallbackManagerForToolRun] = None,
    ) -> str:
        """Use the tool."""
        available_tool_names_str = ", ".join([tool for tool in available_tool_names])
        return (
            f"{requested_tool_name} is not a valid tool, "
            f"try one of [{available_tool_names_str}]."
        )

    async def _arun(
        self,
        requested_tool_name: str,
        available_tool_names: List[str],
        run_manager: Optional[AsyncCallbackManagerForToolRun] = None,
    ) -> str:
        """Use the tool asynchronously."""
        available_tool_names_str = ", ".join([tool for tool in available_tool_names])
        return (
            f"{requested_tool_name} is not a valid tool, "
            f"try one of [{available_tool_names_str}]."
        )


__all__ = ["InvalidTool", "BaseTool", "tool", "Tool"]