Anecdotally, Claude Bug Bot has actually been super impressive in understanding non trivial changes. Like, today, it noted a race condition in a ~1000 line go change that go test -race didnt pick up. There are definitely issues though. For one, it's non deterministic, so you end up with half a dozen commits, with each run noting different issues. For a second, it tends to be quite in favour of premature optimisation. But over all, well worth it in my experience