I let Claude Code run 1,000 inbox placement tests

Every deliverability theory I'd picked up over the years, I tested. Claude Code plus an inbox placement API, testing variations and combinations, on Google and Microsoft.

Over a thousand tests later, I had a rule set and a Claude Code skill instead of a pile of opinions.

The point is the method, not my rules. Your emails have your own edge cases: Loom links, GIFs, images, whatever you send. My rules are a starting point. Lots of placement tests (essentially unlimited on the paid plan) plus AI writing the variations is how you find yours.

One result I still can't get over: a single change to how a link was written moved all 11 test emails from Promotions to Primary. The video shows what it was, plus the Microsoft habit most placement tests miss.

Full video: https://www.youtube.com/watch?v=ByrOheLnWUY&list=PL0Yyhj9Mcbg8zog1pSTOTVfmyHKbtRClF

Go watch it, then tell me what you'd have Claude test first.

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I let Claude Code run 1,000 inbox placement tests