test_command_structured_response_conflicts_with_model_response() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/core/test_wrap_model_call_state_update.py lines 84–113

    def test_command_structured_response_conflicts_with_model_response(self) -> None:
        """Command and model response both setting structured_response raises."""

        class OverrideMiddleware(AgentMiddleware):
            def wrap_model_call(
                self,
                request: ModelRequest,
                handler: Callable[[ModelRequest], ModelResponse],
            ) -> ExtendedModelResponse:
                response = handler(request)
                response_with_structured = ModelResponse(
                    result=response.result,
                    structured_response={"from": "model"},
                )
                return ExtendedModelResponse(
                    model_response=response_with_structured,
                    command=Command(
                        update={
                            "structured_response": {"from": "command"},
                        }
                    ),
                )

        model = GenericFakeChatModel(messages=iter([AIMessage(content="Model msg")]))
        agent = create_agent(model=model, middleware=[OverrideMiddleware()])

        # Two Commands both setting structured_response (a LastValue channel)
        # in the same step raises InvalidUpdateError
        with pytest.raises(InvalidUpdateError):
            agent.invoke({"messages": [HumanMessage("Hi")]})