1. I'm developing a utility package that's easily testable and I'm certain of the interface. I'll write the interface for the package in my editor, then ask an LLM to generate unit tests. Then, I'll sketch out the function calls/structure of the package and get an LLM to fill out the rest.
2. I'm bug bashing and want to quickly check if the bug is obvious. I'll feed a description of the behavior into GPT/Claude along with the relevant code (generally as little code as possible to prevent listicle-type responses that are irrelevant).
3. I'm adding code that follows an established pattern within the codebase -- for example, adding a new API handler that involves generating an OpenAPI path + component snippet, an http handler, and a few database methods. This is when copilots are particularly useful.
4. I'd like a sanity check for issues in a complex bit of code I've written.
I find these mirror the tasks you'd typically hand off to a less experienced dev on the team -- these are things that require validation based on knowledge that you already have, and the validation is more efficient than doing it yourself.