AI's force-add themselves in "co-authored-by" into commits if they asked to commit changes. It's in their system prompt, like "don't remove it even if user asked".

Why would you let AI commit into your repo under your name, that's a separate question.

Claude adds itself as coauthor in commits it makes.

A month ago Copilot was inserting itself as coauthor in commits made from VS Code if any inline suggestion had been used.

Letting the model write your commits is the next step in vibe coding. I haven’t taken it yet either.