BerriAI/litellm · error · UnsupportedParamsError

Azure does not support '{value}' as a {param} param, for api

Error message

Azure does not support '{value}' as a {param} param, for api_version={api_version}. To drop 'tool_choice=required' for calls with this Azure API version, set `litellm.drop_params=True` or for proxy:

`litellm_settings:
 drop_params: true`
Azure API Reference: https://learn.microsoft.com/en-us/azure/ai-services/openai/reference#chat-completions

What it means

Error "Azure does not support '{value}' as a {param} param, for api_version={api_version}. To drop 'tool_choice=required' for calls with this Azure API version, set `litellm.drop_params=True` or for proxy: `litellm_settings: drop_params: true` Azure API Reference: https://learn.microsoft.com/en-us/azure/ai-services/openai/reference#chat-completions" thrown in BerriAI/litellm.

Source

Thrown at litellm/llms/azure/chat/gpt_transformation.py:203

                    if (
                        api_version_year < "2023"
                        or (api_version_year == "2023" and api_version_month < "12")
                        or (api_version_year == "2023" and api_version_month == "12" and api_version_day < "01")
                    ):
                        if litellm.drop_params is True or (drop_params is not None and drop_params is True):
                            pass
                        else:
                            raise UnsupportedParamsError(
                                status_code=400,
                                message=f"""Azure does not support 'tool_choice', for api_version={api_version}. Bump your API version to '2023-12-01-preview' or later. This parameter requires 'api_version="2023-12-01-preview"' or later. Azure API Reference: https://learn.microsoft.com/en-us/azure/ai-services/openai/reference#chat-completions""",
                            )
                    elif value == "required" and (
                        api_version_year == "2024" and api_version_month <= "05"
                    ):  ## check if tool_choice value is supported ##
                        if litellm.drop_params is True or (drop_params is not None and drop_params is True):
                            pass
                        else:
                            raise UnsupportedParamsError(
                                status_code=400,
                                message=f"Azure does not support '{value}' as a {param} param, for api_version={api_version}. To drop 'tool_choice=required' for calls with this Azure API version, set `litellm.drop_params=True` or for proxy:\n\n`litellm_settings:\n drop_params: true`\nAzure API Reference: https://learn.microsoft.com/en-us/azure/ai-services/openai/reference#chat-completions",
                            )
                    else:
                        optional_params["tool_choice"] = value
            elif param == "response_format" and isinstance(value, dict):
                _is_response_format_supported_model = self._is_response_format_supported_model(model)

                if api_version_year is None or api_version_month is None:
                    is_response_format_supported_api_version = True
                else:
                    is_response_format_supported_api_version = self._is_response_format_supported_api_version(
                        api_version_year, api_version_month
                    )
                is_response_format_supported = (
                    is_response_format_supported_api_version and _is_response_format_supported_model
                )

View on GitHub (pinned to 6c2dcb801b)

Solutions

1. Use a supported tool_choice value for this api_version or set drop_params=True.

When it happens

Trigger: Thrown at litellm/llms/azure/chat/gpt_transformation.py:203 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/edc4a4af16246451. Report an issue: GitHub.