I honestly don't think I have.

In this case, using a cheap(er) signal or heuristic as an initial filter before spending more resources on cases that pass the filter is a pattern that shows up all over the place, and LLMs are good at picking up on patterns like that and generalizing them. AFAICT.

I'm not sure how people say this so confidently. I have a rather esoteric haskell library that I've written and published for years. ChatGPT and Claude both know about it and frequently help me improve it, and propose completely novel approaches. I'm really not sure how people are so confident that they can't think of anything new. This seems like wishful confirmation bias.