_format_tool_to_openai_function() — langchain Function Reference

Source Code

libs/core/langchain_core/utils/function_calling.py lines 314–358

def _format_tool_to_openai_function(tool: BaseTool) -> FunctionDescription:
    """Format tool into the OpenAI function API.

    Args:
        tool: The tool to format.

    Raises:
        ValueError: If the tool call schema is not supported.

    Returns:
        The function description.
    """
    is_simple_oai_tool = (
        isinstance(tool, langchain_core.tools.simple.Tool) and not tool.args_schema
    )
    if tool.tool_call_schema and not is_simple_oai_tool:
        if isinstance(tool.tool_call_schema, dict):
            return _convert_json_schema_to_openai_function(
                tool.tool_call_schema, name=tool.name, description=tool.description
            )
        if issubclass(tool.tool_call_schema, (BaseModel, BaseModelV1)):
            return _convert_pydantic_to_openai_function(
                tool.tool_call_schema, name=tool.name, description=tool.description
            )
        error_msg = (
            f"Unsupported tool call schema: {tool.tool_call_schema}. "
            "Tool call schema must be a JSON schema dict or a Pydantic model."
        )
        raise ValueError(error_msg)
    return {
        "name": tool.name,
        "description": tool.description,
        "parameters": {
            # This is a hack to get around the fact that some tools
            # do not expose an args_schema, and expect an argument
            # which is a string.
            # And Open AI does not support an array type for the
            # parameters.
            "properties": {
                "__arg1": {"title": "__arg1", "type": "string"},
            },
            "required": ["__arg1"],
            "type": "object",
        },
    }