If you want to do a version of this yourself quickly --

Install Luanti with Minetest (open source minecraft), and instruct your agent to write a mod that gives it network access to the game's Lua interpreter. The agent can then do anything from modifying the world state directly to controlling NPCs.

I had it build giant bases similar to black mesa in half life with power distribution mods. It would write solvers to optimally place the power cables / repeaters in accordance to the spacial dimensions of the rooms that it would build (lol). I guess this is how I discovered vibe gaming.

I suppose you can have multiple agents interact with each other through that, provided an adapter to proxy agent player navigation and perception to get real information asymmetry between them. Or just emulate / hook the client and do away without a remote Lua mod entirely.