microsoft/autogen · error · ValueError

Model does not support function calling

Error message

Model does not support function calling

What it means

Error "Model does not support function calling" thrown in microsoft/autogen.

Source

Thrown at python/packages/autogen-ext/src/autogen_ext/models/anthropic/_anthropic_client.py:611

                if system_message is not None:
                    # if that case, system message is must only one
                    raise ValueError("Multiple system messages are not supported")
                system_message = to_anthropic_type(message)
            else:
                anthropic_message = to_anthropic_type(message)
                if isinstance(anthropic_message, list):
                    anthropic_messages.extend(anthropic_message)
                elif isinstance(anthropic_message, str):
                    msg = MessageParam(
                        role="user" if isinstance(message, UserMessage) else "assistant", content=anthropic_message
                    )
                    anthropic_messages.append(msg)
                else:
                    anthropic_messages.append(anthropic_message)

        # Check for function calling support
        if self.model_info["function_calling"] is False and len(tools) > 0:
            raise ValueError("Model does not support function calling")

        # Set up the request
        request_args: Dict[str, Any] = {
            "model": create_args["model"],
            "messages": anthropic_messages,
            "max_tokens": create_args.get("max_tokens", 4096),
            "temperature": create_args.get("temperature", 1.0),
        }

        # Add system message if present
        if system_message is not None:
            request_args["system"] = system_message

        has_tool_results = any(isinstance(msg, FunctionExecutionResultMessage) for msg in messages)

        # Store and add tools if present
        if len(tools) > 0:
            converted_tools = convert_tools(tools)

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Remove tools or use a function-calling-capable model

Example fix

Set model_info function_calling=True or drop tools

When it happens

Trigger: Thrown at python/packages/autogen-ext/src/autogen_ext/models/anthropic/_anthropic_client.py:611 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/1c7ff8a80e60acac. Report an issue: GitHub.