microsoft/autogen · error · ValueError

Multiple and Not continuous system messages are not supporte

Error message

Multiple and Not continuous system messages are not supported

What it means

Error "Multiple and Not continuous system messages are not supported" thrown in microsoft/autogen.

Source

Thrown at python/packages/autogen-ext/src/autogen_ext/models/anthropic/_anthropic_client.py:507

            return {"role": "unknown", "content": str(message)}

    def _merge_system_messages(self, messages: Sequence[LLMMessage]) -> Sequence[LLMMessage]:
        """
        Merge continuous system messages into a single message.
        """
        _messages: List[LLMMessage] = []
        system_message_content = ""
        _first_system_message_idx = -1
        _last_system_message_idx = -1
        # Index of the first system message for adding the merged system message at the correct position
        for idx, message in enumerate(messages):
            if isinstance(message, SystemMessage):
                if _first_system_message_idx == -1:
                    _first_system_message_idx = idx
                elif _last_system_message_idx + 1 != idx:
                    # That case, system message is not continuous
                    # Merge system messages only contiues system messages
                    raise ValueError("Multiple and Not continuous system messages are not supported")
                system_message_content += message.content + "\n"
                _last_system_message_idx = idx
            else:
                _messages.append(message)
        system_message_content = system_message_content.rstrip()
        if system_message_content != "":
            system_message = SystemMessage(content=system_message_content)
            _messages.insert(_first_system_message_idx, system_message)
        messages = _messages

        return messages

    def _get_thinking_config(self, extra_create_args: Mapping[str, Any]) -> Dict[str, Any]:
        """
        Get the thinking configuration for API calls

        Args:
            extra_create_args: Extra arguments that may contain thinking config

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Merge system content into a single system message

Example fix

Combine system messages into one before sending

When it happens

Trigger: Thrown at python/packages/autogen-ext/src/autogen_ext/models/anthropic/_anthropic_client.py:507 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/ec4a36181f732715. Report an issue: GitHub.