BerriAI/litellm · error · ValueError

Invalid model format. Expected format: 'model=agent/AGENT_ID

Error message

Invalid model format. Expected format: 'model=agent/AGENT_ID/ALIAS_ID'

What it means

Error "Invalid model format. Expected format: 'model=agent/AGENT_ID/ALIAS_ID'" thrown in BerriAI/litellm.

Source

Thrown at litellm/llms/bedrock/chat/invoke_agent/transformation.py:139

            optional_params=optional_params,
            request_data=request_data,
            api_base=api_base,
            model=model,
            stream=stream,
            fake_stream=fake_stream,
            api_key=api_key,
        )

    def _get_agent_id_and_alias_id(self, model: str) -> tuple[str, str]:
        """
        model = "agent/L1RT58GYRW/MFPSBCXYTW"
        agent_id = "L1RT58GYRW"
        agent_alias_id = "MFPSBCXYTW"
        """
        # Split the model string by '/' and extract components
        parts: Final = model.split("/")
        if len(parts) != 3 or parts[0] != "agent":
            raise ValueError("Invalid model format. Expected format: 'model=agent/AGENT_ID/ALIAS_ID'")

        return parts[1], parts[2]  # Return (agent_id, agent_alias_id)

    def _get_session_id(self, optional_params: dict) -> str:
        """ """
        return optional_params.get("sessionID", None) or str(uuid.uuid4())

    def transform_request(
        self,
        model: str,
        messages: list[AllMessageValues],
        optional_params: dict,
        litellm_params: dict,
        headers: dict,
    ) -> dict:
        # use the last message content as the query
        query: Final[str] = convert_content_list_to_str(messages[-1])
        return {

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Use model format 'agent/AGENT_ID/ALIAS_ID'.

When it happens

Trigger: Thrown at litellm/llms/bedrock/chat/invoke_agent/transformation.py:139 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@6c2dcb801b (2026-08-15). Data as JSON: /api/errors/63d3ed55bbabc40f. Report an issue: GitHub.