Easily 99 percent on most tasks. As an example, for a Python project with a dozen modules and ~50 files,a simple instruction like "Design a config file backed by Pydantic to store the project's settings. Keep the models modular" sets up nested Pydantic models, moves the settings to sensibly named JSON fields and updates the code to use Pydantic classes everywhere. Takes a few minutes maybe. Manually done the same task would take me half a few hours in the best case and a day in the worst case.