BerriAI/litellm · error · UnsupportedParamsError

Azure OpenAI does not support reasoning_effort='none' for th

Error message

Azure OpenAI does not support reasoning_effort='none' for this model. Supported values are: 'low', 'medium', and 'high'. To drop this parameter, set `litellm.drop_params=True` or for proxy:

`litellm_settings:
 drop_params: true`
Issue: https://github.com/BerriAI/litellm/issues/16704

What it means

Error "Azure OpenAI does not support reasoning_effort='none' for this model. Supported values are: 'low', 'medium', and 'high'. To drop this parameter, set `litellm.drop_params=True` or for proxy: `litellm_settings: drop_params: true` Issue: https://github.com/BerriAI/litellm/issues/16704" thrown in BerriAI/litellm.

Source

Thrown at litellm/llms/azure/chat/gpt_5_transformation.py:112

        api_version: str = "",
    ) -> dict:
        reasoning_effort_value = non_default_params.get("reasoning_effort") or optional_params.get("reasoning_effort")
        effective_effort: Final = _get_effort_level(reasoning_effort_value)

        # gpt-5.1/5.2/5.4 support reasoning_effort='none', but other gpt-5 models don't
        # See: https://learn.microsoft.com/en-us/azure/ai-foundry/openai/how-to/reasoning
        supports_none: Final = self._supports_reasoning_effort_level(model, "none")

        if effective_effort == "none" and not supports_none:
            if litellm.drop_params is True or (drop_params is not None and drop_params is True):
                non_default_params = non_default_params.copy()
                optional_params = optional_params.copy()
                if _get_effort_level(non_default_params.get("reasoning_effort")) == "none":
                    non_default_params.pop("reasoning_effort")
                if _get_effort_level(optional_params.get("reasoning_effort")) == "none":
                    optional_params.pop("reasoning_effort")
            else:
                raise UnsupportedParamsError(
                    status_code=400,
                    message=(
                        "Azure OpenAI does not support reasoning_effort='none' for this model. "
                        "Supported values are: 'low', 'medium', and 'high'. "
                        "To drop this parameter, set `litellm.drop_params=True` or for proxy:\n\n"
                        "`litellm_settings:\n drop_params: true`\n"
                        "Issue: https://github.com/BerriAI/litellm/issues/16704"
                    ),
                )

        result: Final = OpenAIGPT5Config.map_openai_params(
            self,
            non_default_params=non_default_params,
            optional_params=optional_params,
            model=model,
            drop_params=drop_params,
        )

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Use reasoning_effort low/medium/high for this Azure model, or set litellm.drop_params=True.

When it happens

Trigger: Thrown at litellm/llms/azure/chat/gpt_5_transformation.py:112 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/ce1afb3ff4380602. Report an issue: GitHub.