rehan-remade /
universal-modder
Skills and a CLI that let AI coding agents mod PC games you own
- 8.7k stars
- Python
- Updated today
- Some experience
- Coding agents & dev tools
Modding a game usually means working out the engine, finding the right loader, reading decompiled code, making art and sound, and testing in the running game. This project packages that work as skills in the Agent Skills format, so an agent can follow the same loop each time.
The loop starts with a search of a knowledge base of field notes, then recon of the game, a safe lab with backed-up saves, reading the real code, building one working slice, generating assets, testing in the game, recording and packaging. At the end, the agent can write a field note and open a pull request so the next agent starts with what it learned.
It works with several agents: Claude Code, Codex, Gemini CLI, Copilot, Cursor and OpenCode. Asset generation uses fal, which needs an API key. The README also names ComfyUI for local images and two paid sprite services as options.
What it does
Skills for the whole modding loop
Skills cover game recon, reverse engineering, asset generation, an asset pipeline, game automation, showcase videos, mashup mods, publishing and porting. The main skill includes playbooks for many engines, such as Unity, Unreal, Godot, Source and GameMaker.
Field-note knowledge base
The knowledge folder holds notes on how specific games were modded, with working versions, the route taken, how it was verified and the gotchas. The um kb commands search, create, check and submit notes.
The um CLI
A Python command-line tool for fal asset generation, key storage, knowledge base search and pull requests. It also supports ComfyUI, Sprixen and Voidless for images and sprites.
fal MCP for art, 3D and audio
The fal tools generate sprites, textures, image-to-3D models, sound effects, music, voice and cutscene video. The asset pipeline then fits them to a game's exact frame and palette needs.
Optional three-agent team
For long mods, an orchestrator checks the work of a game worker, which touches the running game, and an offline worker, which does not. The README warns this uses several times the tokens of one agent.
What you could build
- Add a new weapon or item with generated sprites to a game like Terraria.
- Research what engine a game uses and whether anyone has modded it before.
- Port content from one game into another, such as a vehicle into Minecraft.
- Record and cut a showcase video of a finished mod.
- Write up a field note on a mod you made so others can build on it.
Get started
Install the plugin for your agent. For Claude Code, run the two plugin commands below. Install the um CLI with uv, add a fal API key with um fal key set if you want generated assets, then ask your agent to mod a game. You also need Git, Python 3.10+ and ffmpeg.
/plugin marketplace add rehan-remade/universal-modder/plugin install universal-modder@universal-modderuv tool install git+https://github.com/rehan-remade/universal-modderCommands are copied from the project's README. Read it on GitHub for the full setup.
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