This latest crop of frontier models (Fable, Sol) are very good at broad exploratory directions like "audit for bugs" or "find places in this codebase that I custom-implemented functionality that has since become available in the libraries I am using" in ways that prior generations would fail or not return as high quality results.

I did a recent head-to-head comparison between Qwen 3.6 35B running locally and Fable on the above and while Qwen did an admirable job finding a good handful of things, Fable returned many more, and more serious, issues. This included many more issues that crossed system boundaries in a multi-service repo.

In terms of one-shot "follow these detailed instructions" I think we are at a point where frontier models are overkill, especially at the price. For broad fan-out explorations, I think we are just getting started.