ModTestBridge

For mod developers, not players. If you just play Valheim, you don't need this.

This mod lets scripts, or an AI coding agent such as Claude Code, drive Valheim while you develop a mod:

• run console commands and get back what they printed;
• read the BepInEx log;
• see whether you're at the menu or in a world, and where;
• quit cleanly, saving first;
• relaunch straight into a test world with an existing character, with no menus.

Your mod keeps its own in-game test commands; the bridge just runs them and reads the results. So you build, restart, test and read the failures without clicking through anything.

⚠️ Development profiles only

• Off until you turn it on: set Enabled = true in BepInEx/config/Spronglehump.ModTestBridge.cfg.
• It listens on 127.0.0.1 only, and every request needs a random token.
• Even so, anything on your computer with that token can run console commands. Never install it on a server or on a profile you play on.

Everything else is on GitHub

https://github.com/tmac1973/ModTestBridge

You'll find:

• setup and the full guide: the HTTP API, autostart, backups;
• mtb, the command-line client: mtb restart, mtb run "mymod_test all" "[TEST] done", mtb doctor...;
• the Claude Code plugin, a skill that teaches Claude to test your mod in-game: /plugin marketplace add tmac1973/ModTestBridge;
• how to write in-game tests for your mod, with an example mod and a test-runner script.