test_command_with_extra_messages_and_model_response() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call_state_update.py lines 57–82

    def test_command_with_extra_messages_and_model_response(self) -> None:
        """Middleware can add extra messages via command alongside model messages."""

        class ExtraMessagesMiddleware(AgentMiddleware):
            def wrap_model_call(
                self,
                request: ModelRequest,
                handler: Callable[[ModelRequest], ModelResponse],
            ) -> ExtendedModelResponse:
                response = handler(request)
                summary = HumanMessage(content="Summary", id="summary")
                return ExtendedModelResponse(
                    model_response=response,
                    command=Command(update={"messages": [summary]}),
                )

        model = GenericFakeChatModel(messages=iter([AIMessage(content="Hello!")]))
        agent = create_agent(model=model, middleware=[ExtraMessagesMiddleware()])

        result = agent.invoke({"messages": [HumanMessage(content="Hi")]})

        messages = result["messages"]
        assert len(messages) == 3
        assert messages[0].content == "Hi"
        assert messages[1].content == "Hello!"
        assert messages[2].content == "Summary"