I've been using Claude Code with Opus 4.5 a lot the last several months and while it's amazingly capable it has a huge tendency to give up on tests. It will just decide that it can commit a failing test because "fixing it has been deferred" or "it's a pre-existing problem." It also knows that it can use `HUSKY=0 git commit ...` to bypass tests that are run in commit hooks. This is all with CLAUDE.md being very specific that every commit must have passing tests, lint, etc. I eventually had to add a Claude Code pre-command hook (which it can't bypass) to block it from running git commit if it isn't following the rules.
I haven't seen it bypass my hook yet (knock on wood). I have my hook script [0] tell that its commits are required to pass validation, maybe that helps push it in the right direction?