@Eugene Seva and I jumped on a video meet after I commented on one of his posts. He shared the GitHub repo of his work with me. A cool build of a Japanese digital business card for realtors. QR code, AI chat, mortgage calculator. Live site, paying customers, 140 merged pull requests, still shipping daily. Good build. I spent the day trying to work out the Western version. Never got there. What I got instead was better. That product works because the company behind it is a Tokyo brokerage sitting on 4.5 million sales records and 6,000 new listings a day. The app is a skin over a filing cabinet they already owned. Take the data away and it's a link-in-bio page with a chatbot attached. In the US that data is MLS-licensed per organization, and you need a contract with each one even going through an aggregator. That's a funded-company problem, not a weekend one. So I went looking for something that runs on nothing licensed. Six shapes, six walls. Business cards lose to a free tier with 150,000 reviews. Valuation needs an AVM license. Chat and nurture is held by people charging $395 a month. The fifth one nearly got me. Since 2024, buyers sign a written agreement about agent compensation before touring a house, and everyone is confused by it. No tool exists. I had the whole thing designed. Then I checked whether a real estate agent is permitted to explain a contract to a client. They are not. That's unauthorized practice of law, in all fifty states, and it's the agent handing the document over who carries the exposure. Insurers started writing generative-AI exclusions in January, so it wouldn't be covered either. Here's the part you'll care about. The constraint ended up as the folder structure. "Never produce client-addressed output" is a rule, and a rule sitting in rules.md is a suggestion. So it's also a check script. It reads every skill file, and if a client salutation turns up in one, it exits 1. Same for listing data. Each skill declares its inputs in a table, and the check fails if any input is a source we can't legally touch.