The cost cascade, applied to fixes: the cheap worker gets the first round; when its page still fails the checks, the next round goes to a stronger model instead of the same one again. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01UpT7eWzeLhRwuYmsSQnbRb