I'm working on something similar. I'm building a MUD with an LLM playing the role of GM. Currently it just controls NPCs, but I eventually want it to be able to modify the game rules in real time. My end goal is a world that hundreds of players can play in simultaneously, but has the freedom and flexibility of a TTRPG (while still remaining balanced and fair).

That's really cool, Elias. I keep seeing people try to put LLMs into the role of the GM. But I think you're doing something new and important by working to have the rules available to it.

Is your project available anywhere? Best of luck!

If you're interested, because I kept seeing "LLM as GM" projects, I got curious about how well it would work to have LLMs as players instead. So I made this:

https://github.com/maxwelljoslyn/gm-trainer

It's a training ground for GMs to practice things like spontaneous description, with 4 AI players that get fed what each other say so they act in a reasonably consistent manner. It's not perfect, but I've gotten some good use out of it.