BerriAI/litellm · error · ValueError

COMPACT responses is not supported for {custom_llm_provider}

Error message

COMPACT responses is not supported for {custom_llm_provider}

What it means

Dispatch guard in the Responses API compact path: no BaseResponsesAPIConfig implementing compaction was found for the resolved custom_llm_provider, so the COMPACT operation is unsupported for that provider.

Source

Thrown at litellm/responses/main.py:1891

            model=model,
            custom_llm_provider=custom_llm_provider,
            litellm_params=litellm_params,
            local_vars=local_vars,
        )

        if custom_llm_provider is None:
            raise ValueError("custom_llm_provider is required but passed as None")

        # get provider config
        responses_api_provider_config: Final[BaseResponsesAPIConfig | None] = (
            ProviderConfigManager.get_provider_responses_api_config(
                model=model,
                provider=custom_llm_provider,
            )
        )

        if responses_api_provider_config is None:
            raise ValueError(f"COMPACT responses is not supported for {custom_llm_provider}")

        local_vars.update(kwargs)

        # Build optional params for compact endpoint
        response_api_optional_params: Final[ResponsesAPIOptionalRequestParams] = (
            ResponsesAPIRequestUtils.get_requested_response_api_optional_param(local_vars)
        )

        # Get optional parameters for the responses API
        request_drop_params: Final = kwargs.get("drop_params")
        responses_api_request_params: Final[dict] = ResponsesAPIRequestUtils.get_optional_params_responses_api(
            model=model,
            responses_api_provider_config=responses_api_provider_config,
            response_api_optional_params=response_api_optional_params,
            allowed_openai_params=None,
            drop_params=request_drop_params if isinstance(request_drop_params, bool) else None,
        )

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Use a provider that supports COMPACT responses.

When it happens

Trigger: Thrown at litellm/responses/main.py:1891 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/dbdbdec3e4d4c74b. Report an issue: GitHub.