No, I don't trust AI to do much of anything. I've written in other comments on HN that I mostly use it to write draft commit messages and pull requests that I review and rewrite myself, now that the honeymoon phase has ended. But when I was still attempting to get it to do more, I found Claude Code was really bad at trying to fix conflicted merges and rebases, always dropping the wrong parts of the code and leaving me with a broken codebase and a commit message history that didn't make sense for the changes inside.
That said, "jj new -A @", get Claude to do it's thing, "jj squash" is going to be pretty safe.