The Graphcool Permission system is super interesting because it ads a surprising amount of expressive power to a declarative permission system. We actually brought over the idea to prisma-binding https://www.npmjs.com/package/prisma-binding by including the `exists` query. For now you have to manually perform the check in resolvers, so it is not a complete substitute.
Speaking of permissions in Prisma in general. For now it includes a fairly primitive token based system: You either have full access or no access at all. In the future we will add more fine-grained grants so you can give some users read access to specific types while preventing data mutations for example. The details are still being worked out, and this system will not be as flexible as Permission Queries in Graphcool Framework.