I'm a solo dev with ADHD. I built Petipa, an app inside ChatGPT that saves your plans and shows you one step a day. I submitted it to OpenAI on October 17 and it's still in review, so this is about getting ready to submit, not about getting approved. Here's what surprised me:
1. The review cares how you split your tools. Your app is a set of tools that ChatGPT can call. Each one should do a single thing, and any tool that deletes data has to be marked that way. I had to split a few of mine before submitting.
2. Cards are tiny on purpose. A card can have at most two buttons. That's great for a focus app like mine. It's hard if your product is a dashboard.
3. You can't sell inside ChatGPT. The way I read OpenAI's rules, nothing your app shows in ChatGPT can name a paid plan, show a price or link to checkout. When someone hits a limit, you tell them plainly and offer their own options. Billing lives on your own website, so plan your funnel around that from day one.
4. Don't trust the model to carry state. ChatGPT sometimes drops arguments between calls, so a confirmation code you hand it for a delete may never come back. Keep the truth on your server, make every write safe to repeat, and run delete confirmations on the server side.
5. The reviewer needs a demo account that keeps working. It needs sample data, and it has to survive however long the review takes. I reset mine every day. You also need live privacy and terms pages published under the same name as your verified identity.
If you're thinking about building one, I'm happy to answer questions in the comments.
Petipa: https://petipa.app