test_unified_error_messages() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_call_limit.py lines 535–559

def test_unified_error_messages() -> None:
    """Test that error messages instruct model not to call again for both run and thread limits.

    Previously, only thread limit messages included 'Do not' instruction.
    Now both run and thread limit messages should include it.
    """
    middleware = ToolCallLimitMiddleware(thread_limit=10, run_limit=1, exit_behavior="continue")
    runtime = None

    # Test with run limit exceeded (thread limit not exceeded)
    state = ToolCallLimitState(
        messages=[AIMessage("Response", tool_calls=[{"name": "search", "args": {}, "id": "2"}])],
        thread_tool_call_count={"__all__": 1},  # Under thread limit
        run_tool_call_count={"__all__": 1},  # At run limit, next call will exceed
    )
    result = middleware.after_model(state, runtime)  # type: ignore[arg-type]
    assert result is not None

    # Check the error message includes "Do not" instruction
    error_messages = [msg for msg in result["messages"] if isinstance(msg, ToolMessage)]
    assert len(error_messages) == 1
    error_content = error_messages[0].content
    assert "Do not" in error_content, (
        "Run limit error message should include 'Do not' instruction to guide model behavior"
    )