autogen - 💡(How to fix) Fix _rstrip_last_assistant_message only strips trailing whitespace from the content — it does not remove the assistant message.

        from autogen_ext.models.anthropic import AnthropicChatCompletionClient

        class _AnthropicClient(AnthropicChatCompletionClient):
            # autogen-ext 0.7.x only whitespace-strips trailing assistant messages;
            # Anthropic API requires the conversation to end with a user message.
            def _rstrip_last_assistant_message(self, messages: Sequence[_LLMMessage]) -> Sequence[_LLMMessage]:
                msgs = list(messages)
                while msgs and isinstance(msgs[-1], _AssistantMessage):
                    msgs.pop()
                return msgs

        return _AnthropicClient(
            model=model_name,
            api_key=llm_key,
        )