extra = Extra.ignore
    @property
    def requires_reference(self) -> bool:
        """Whether this evaluator requires a reference label."""
        return False
    @property
    def _tools_description(self) -> str:
        """Get the description of the agent tools.
        Returns:
            str: The description of the agent tools.
        """
        if self.agent_tools is None:
            return ""
        return "\n\n".join(
            [
                f"""Tool {i}: {tool.name}
Description: {tool.description}"""
                for i, tool in enumerate(self.agent_tools, 1)
            ]
        )
[docs]    @staticmethod
    def get_agent_trajectory(
        steps: Union[str, Sequence[Tuple[AgentAction, str]]]
    ) -> str:
        """Get the agent trajectory as a formatted string.
        Args:
            steps (Union[str, List[Tuple[AgentAction, str]]]): The agent trajectory.
        Returns:
            str: The formatted agent trajectory.
        """
        if isinstance(steps, str):
            return steps
        return "\n\n".join(
            [
                f"""Step {i}:
Tool used: {action.tool}
Tool input: {action.tool_input}
Tool output: {output}"""
                for i, (action, output) in enumerate(steps, 1)
            ]
        )
    @staticmethod
    def _format_reference(reference: Optional[str]) -> str:
        """Format the reference text.
        Args:
            reference (str): The reference text.
        Returns:
            str: The formatted reference text.
        """
        if not reference:
            return ""
        return f"""
The following is the expected answer. Use this to measure correctness: