As does everyone. Ideas are always great until you need to actually start writing, then you find out how little those amazing ideas are actually worth.
Anyway, here’s what CoG has to say about AI-powered spell checkers in regards to hosted games:
We permit but strongly discourage the use of AI grammar checkers (including Grammarly). Using a grammar checker to detect grammar errors and fix them yourself is fine, but Grammarly and other AI grammar checkers will cheerfully “fix” grammar issues automatically, or, worse, just rewrite (or even write) large chunks of text for you. If you use a lot of AI to write your game, your work will sound like an AI, which is bad, and we might not be able to publish the game, because the AI wrote the game, not you.
It’s on their site. Of course, those rules only cover actual submissions to HG; You’re allowed to use whatever you want for your demo or hobby project and it’s highly unlikely anyone will mind. Except perhaps you, once you realize how annoying Grammarly is when you give it anything more creative than a workplace email.