You commented MOD, so here is the whole thing: the repo link, a 2 minute install and 5 prompts you can paste straight into Claude Code. You do not need to know how to mod a game to follow along. We go step by step.
What it is
universal-modder is a free, MIT licensed toolkit on GitHub with 7.4K stars. It plugs skills, tools and a shared knowledge base into the AI coder you already use, so it can mod almost any PC game you own.
You describe the mod in plain English. The agent finds the game, works out the engine, reads the real code, builds the mod, makes the art, 3D and sound, tests it in the running game and even cuts a video of it.
Six mods made by AI agents: Minecraft in GTA V, Halo's Warthog in Minecraft and more. From the repo README.
People have already used it to put real Minecraft inside GTA V story mode (Minecraft mobs fight the police), port Halo's Warthog into Minecraft and add a brand new civilization to Age of Empires II.
Before you start
A PC game you own. Single player, or a server you host yourself.
Claude Code (Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode work too).
Git, Python 3.10 or newer and ffmpeg. Blender only if you want 3D models turned into sprites.
About 2 minutes for the install.
Step 1: install it in Claude Code
Open Claude Code and run these two commands, one after the other:
/plugin marketplace add rehan-remade/universal-modder/plugin install universal-modder@universal-modderThat gives Claude the modding skills, the asset tools and the um command line tool in one go.
Using another agent? The README has a one line install for each one. Codex, for example:
codex plugin marketplace add rehan-remade/universal-moddercodex plugin add universal-modder@universal-modderStep 2: ask your first question
Start small so you see how it thinks. Point it at a game folder and ask:
What engine is [path to your game folder], and has anyone modded it before?Every run follows the same loop: search the knowledge base, scan the game, pick a route, back up your saves, read the actual code, build one working piece, make the assets, check it in the real game, package it and write a field note for the next agent.
The kit: 5 prompts to paste
These come straight from the repo's own examples. Swap the game for one you own.
1. Add new weapons
Mod Terraria: add a homing missile launcher and a tactical nuke that craters the world. Make the sprites with fal.2. Add a whole new faction
Make a new civilization for Age of Empires II with a unique unit rendered from 3D.3. Put one game inside another
Put real Minecraft inside GTA V story mode. Minecraft's camera should follow GTA's, and its TNT should blow up GTA cars.4. Port a vehicle between games
Port the Warthog from my Halo install into Minecraft, with a gunner on the turret.5. Your own idea
Mod [game I own]: add [the thing you want]. Back up my saves first, show me your plan before you change anything, then test it in the running game.The free route for art, no API key
By default the art, 3D and sound come from fal, which needs a fal API key (paid usage). If you just want images for free, the toolkit can use a ComfyUI server running on your own computer instead:
um comfy statusum comfy imageAdd --sprite to the image command and it cuts the result out as a game sprite. No key, no bill.
How the art gets made: concept, 3D model, then a sprite that works in the game. From the repo README.
The safe way to start
It backs up your saves before it touches anything. You can also snapshot them yourself with
um backup.It asks first before driving your mouse and keyboard, installing loaders into game folders or publishing anything.
It stays away from online games with anti cheat. No cheats against other players and no bypassing DRM. Stick to single player games and servers you host.
It never ships game files. Mods go out as your own code and assets.
Who this is for
Anyone who ever wished a game had one more weapon, one more map or one wild crossover. If you have Claude Code and a game you love, install it tonight and ask your first question.
The AI Leverage is how a few thousand builders get sharper every week: the tools that quietly change the game, and the exact way to run them, so AI saves you real time and real money instead of just adding another tab. Come get better with us. by bestapps.ai on instagram.
