Comment by ElFitz

I had some successes refactoring one instance of a pattern in our codebase, along with all the class' call sites, and having codex identify all the others instances of said pattern and refactor them in parallel by following my initial refactor.

Similarly, I had it successfully migrate a third (so far) of our tests from an old testing framework to a new one, one test suite at a time.

We also had a race condition, and providing Claude Code with both the unsymbolicated trace and the build’s symbols, it successfully symbolicated the trace, identified the cause. When prompted, it identified most of the similar instances of the responsible pattern in our codebase (the one it missed was an indirect one).

I didn’t care much about the suggested fixes on that last one, but consider it a success too, especially since I could just keep working on other stuff while it chugged along.