The real goal would be for the model to determine what tool is needed to achieve the task, and use that to achieve it. Using the model to write code provides a way to achieve explainable and correctness guarantees (by reading and executing the code, not the model internals). So in this case identifying that a diff program is required may have taken a couple of seconds, ans the diff would take milliseconds - still yielding a faster and more correct output (as the model alone may produce an approximate diff or hallucinate).