Troubleshooting

Read what the box on the screen says: it ends with the path to the log, and the log has the rest.

Windows warns about an unrecognised program

Choose More info, then Run anyway. The builds are not signed: a certificate costs a few hundred euros a year.

macOS refuses to open it

The game is not signed by Apple, so a copy a browser downloaded will not open. Install it from a terminal instead, which keeps your games:

curl -fsSL https://rexmundi.alexisbouchez.com/install.sh | sh

curl -fsSL https://rexmundi.alexisbouchez.com/install.sh | sh

Linux says permission denied

A download is not executable until you say so:

chmod +x rexmundi-linux-x64.AppImage

chmod +x rexmundi-linux-x64.AppImage

Linux says it needs FUSE

An AppImage mounts itself, and older distributions do not ship what that takes. Install it (libfuse2 on Debian and Ubuntu, fuse2 on Arch), or run the file without it:

./rexmundi-linux-x64.AppImage --appimage-extract-and-run

./rexmundi-linux-x64.AppImage --appimage-extract-and-run

It says no supported GPU

The game draws through Vulkan on Linux and Windows, Direct3D 12 on Windows, and Metal on macOS. Update the graphics driver. On Linux, install your card's Vulkan driver: vulkan-radeon, vulkan-intel or the NVIDIA driver, depending on the card.

It says cannot open a window

There is no screen to open it on. Over SSH or on a server, there is nothing to be done: the game needs a desktop.

That is a crash, and it leaves a report. Look in the logs folder for the newest crash-<date>.txt, which names what killed the game and where in the program it was. Send it with the log beside it.

This is the plain archive, not the installer, the disk image or the AppImage: those three carry everything inside them. An unpacked copy reads its map, its agent tool and SDL from the folder the game sits in, so keep what you unpacked together. A shortcut to the executable is fine; moving the executable out on its own is not. On macOS, move the whole application, not what is inside it.

The assets line of the report says which files are missing. If one of them is, download it again.

Check the assets line of the report first: a missing earth.cube is a globe with nothing on it, and the file is some 75 MB, so a download that stopped early loses it.

If the log says this GPU cannot sample DXT1 (BC1) textures, the driver is older than the game needs. Update it.

The game has no AI of its own. A coding agent you already have plays everyone else, and the game has to be able to find it.

Open the menu with Escape, then Settings, and look under Game master. The page says whether that agent is on this machine. There is nothing else to set up: Play turn tells the agent which commands to run.

The game looks for the agent on your PATH. A game started from Finder, from Explorer or from a desktop launcher does not always get the same PATH as your terminal, so an agent installed in your home folder can be there and still not be found. Two cures: start the game from a terminal, or put the command in settings.json next to your games, with {prompt} where the game puts its prompt:

{ "agent": "claude", "command": ["/home/you/.local/bin/claude", "-p", "{prompt}", "--allowedTools", "Bash(rexmundi-agent:*)"] }

An agent the settings do not list plays the same way, from its shell. Give its command in settings.json the same way, and let it run rexmundi-agent, which the game puts on its PATH for the turn. To see what it will be told, run:

rexmundi-agent guide                      # Windows, macOS, an unpacked copy
./rexmundi-linux-x64.AppImage guide       # Linux

The window and the agent meet in one folder, and each has to be looking at the same one. Ask them both:

rexmundi --diagnose        # the "data" line
rexmundi-agent doctor      # the "games in" line

On Linux both are the AppImage:

./rexmundi-linux-x64.AppImage doctor

If the two disagree, REXMUNDI_HOME is set for one of them and not for the other. Set it for both, or for neither.

The game updates itself from the menu: Escape, then the version along the foot. It fetches with curl and unpacks with tar, which Windows, macOS and Linux all ship, and it writes into its own folder.

So the folder has to be writable. The Windows installer asks for no administrator and puts the game in your own user folder, which is writable; a copy moved into Program Files by hand is not. On Linux the file it replaces is the AppImage itself, so the folder holding that has to be yours to write in. The page in the game says what went wrong; the log says it at greater length.

Downloading the game again from the front page does the same job by hand. Your games are kept elsewhere and are not touched by it.

In the folder the logs sit in, one folder up: %APPDATA%\RexMundi, ~/Library/Application Support/RexMundi or ~/.local/share/RexMundi. Each game is a folder under games, holding what happened as a line per turn. Copy one to branch a timeline, or delete it to be rid of it. Removing the game itself leaves all of it where it is.

Settings turns off the clouds, the glowing borders and the province borders. Each is drawn every frame, and the clouds cost the most. The window also draws less when it is smaller.