Rule Referee started at a family game night where we spent more time arguing about Mexican Train rules than actually playing. I built a search engine that pulls answers directly from real rulebooks, not AI-generated guesses. It's deterministic, not generative. It's designed to say it doesn't know rather than make something up. Currently 15 games including Catan, Exploding Kittens, Chess, Mexican Train, and more. Chess and 3 games of your choice or $2.99/month for all access. iOS only for now.