Rex Mundi
A geopolitical sandbox, playable with your favorite coding agent.
Join the Discord serverDemo
Download the game
Version 0.0.8, released 24 September 2026
Or install from a terminal
On macOS and Linux, one line downloads it, checks it and installs it:
curl -fsSL https://rexmundi.vercel.app/install.sh | sh
curl -fsSL https://rexmundi.vercel.app/install.sh | sh
It also puts rexmundi and rexmundi-agent on your PATH, so the game and its game master tools answer from any terminal.
With your agent
Your coding agent can download the game, install it, start it and sign itself up as game master. Paste it this prompt:
Install Rex Mundi on this machine and run it, then be my game master.
1. On macOS or Linux, run this, which downloads the game, checks it, installs it where the system expects it and starts it (on a Mac, in Applications with nothing for Gatekeeper to refuse; on Linux, in the application menu and as `rexmundi` on the PATH):
curl -fsSL https://rexmundi.vercel.app/install.sh | sh
2. On Windows, download rexmundi-windows-x64-setup.exe from the latest release at https://github.com/alexisbcz/rexmundi-downloads/releases/latest and run it; it needs no administrator.
3. Start the game, so I get its window.
4. Make yourself its game master: open the menu with Escape, then Settings, and pick yourself under Game master if you are Claude Code, Codex, OpenCode, Mistral Vibe or Pi. Nothing else needs setting up: Play turn runs you from your shell with the rexmundi-agent command. If you are another agent, put your own command in settings.json with {prompt} where the prompt goes, and run `rexmundi-agent guide` to see what you will be asked to do.
5. Tell me how to start a game in the window and how to send you a turn.
Fix whatever fails along the way; ask me only about what you cannot decide yourself.As a plain archive
- Windows, 64-bit (.zip)
- Linux, x64 (.tar.gz)
- Linux, ARM (.tar.gz)
- macOS (Intel and Silicon) (.tar.gz), not signed by Apple
A folder you can move anywhere, as long as what is in it stays together. The game updates itself either way.