Jester David
Hero
It's a bit funky. The Fan Site Kit says to use the GSL for any content on your website, but the GSL explicitly only covers PDFs as electronic products.Did I sign some GSL without knowing it? OGL limited you more than US copyright law it just enabled somebody to use certain specific ip and trademarks while limiting you more in other ways.
So if you're generating you have to stick to what is permitted via US copyright law. Which means no trademarks, IP, and the like. Which includes (but is not limited to) terms such as "Dungeons & Dragons", "Player's Handbook", "Dungeon Master", "Dragonborn", "Eladrin", and the like. Monsters and power statblocks also have to look different, as that's WotC's trade dress.
While you cannot copyright game mechanics, the actual written rules are copyrighted. So you'd need to rewrite every single rule and rephrase it. And it'd be a good idea to consult a lawyer to find out where the line is; i.e. how many words you can use in a row. If terms like "basic melee attack" are generic enough or not.