Every time Claude tells me something's done, a second Claude checks it. AI tools say "done" when it isn't more often than you'd think. In marketing that's the scheduled post that never made it into the queue, the email draft that didn't save, or the CRM record with the wrong date on it. Usually you only find out when the post doesn't go out. So since July, whenever Claude changes something I'm going to rely on, it hands the check to a fresh Claude. That one hasn't seen the work. It's only told what should now be true, and if it's all fine it just replies with one word. I don't even see it unless something's wrong. Today, for example, it checked Friday's LinkedIn post had saved properly and was down for the right time. It checked a handful of emails were sitting in my drafts saying what they should, too. It ran 12 times altogether. It has to be a fresh one. The Claude that did the work already thinks it did it, so it reads everything back expecting it to be right. As Sabrina Ramonov puts it, "no grading its own homework". My first version had a flaw I only found by asking a question. Claude had set it to check only when three or more things had changed. I asked who decides that, and the answer was Claude, the same Claude the check was there to keep an eye on. So we took the number out. One change I'm relying on is enough. It was still just a rule Claude was supposed to follow, though. Today I asked for it to be properly automatic, so now there's a hook, a small script Claude Code runs at the end of every reply. If Claude changes something and hasn't started a check, the hook stops it and tells it to start one. We ran today's session through it first, and it would have caught four times Claude skipped the check, one of them moving something in my calendar. If you've got Claude scheduling posts, writing to your CRM or drafting emails for you, I'd say it's worth setting up. Anyone else got AI checking AI on their marketing, or do you check it all yourself?