My site was quietly losing email subscribers. The signup form sent a confirmation email. But everything looked fine. And yet, email subscribers never reached my list for my local newsletter project list. And I got no notifications. A weekly digest I built tipped me off: 7 signups I had never seen. So I pointed Claude Code at the repo with one rule: investigate first, fix nothing. It found the cause in minutes. Full debugging session: https://www.youtube.com/watch?v=eWQ5Bku7rgg Watch it on...