How to install and use universal-modder, the open-source toolkit that lets AI coding agents mod PC games you own.
📘 Full guide with the game library, costs and changelog: universal-modder.dev · Quick reference: Google Sites guide
This is an unofficial, community guide. It contains no code from universal-modder, so install the toolkit only from the official repository.
| Official repo | rehan-remade/universal-modder |
| Maintainer | rehan-remade |
| Stars / forks | 5.7k+ / 540+ (October 2026) |
| License | MIT, free |
| Agents | 7 install routes (table below) |
- What it is
- Requirements
- Three ways to install
- Install by agent (7 routes)
- Set up fal
- Your first mod
- Common errors
- FAQ
Universal Modder gives your agent:
- 11 Agent Skills, led by
mod-any-game. It runs the same 10-step loop every time: search the knowledge base, recon, set up a safe lab, read the real code, build one working slice, generate assets, verify in game, record, package, write a field note. 12 engine playbooks back it up (Unity, Unreal, .NET/XNA, Godot, Source, Bethesda, Minecraft, AoE2, RE Engine/FromSoft/GTA, native C++, indie engines, retro decomps). - The
umCLI:scan,fal,comfy,sprite,render3d,win,video,backup,publish check,kb. - A fal MCP server for sprites, textures, 3D, SFX, music and voice.
- A knowledge base of field notes on how specific games were modded.
| Need | Notes |
|---|---|
| AI coding agent | Claude Code needs a Pro/Max/Team/Enterprise plan or API billing |
| Git, Python 3.10+, ffmpeg | required |
| uv | recommended for the CLI |
| fal API key | only for generated assets |
| Blender | only for 3D → sprite renders |
Windows: winget install Git.Git Python.Python.3.12 astral-sh.uv Gyan.FFmpeg
macOS: brew install git python ffmpeg uv
1. Plugin (Claude Code shown; other agents in the next table)
/plugin marketplace add rehan-remade/universal-modder
/plugin install universal-modder@universal-modder
2. Clone and start your agent inside the folder
git clone https://github.com/rehan-remade/universal-modder3. CLI only. um is installed from GitHub; it is not on PyPI, so pip install universal-modder won't work.
uv tool install git+https://github.com/rehan-remade/universal-modder
# or
pipx install git+https://github.com/rehan-remade/universal-modder| Agent | Install |
|---|---|
| Claude Code | /plugin marketplace add rehan-remade/universal-modder then /plugin install universal-modder@universal-modder |
| Codex | codex plugin marketplace add rehan-remade/universal-modder then codex plugin add universal-modder@universal-modder |
| Gemini CLI | gemini extensions install https://github.com/rehan-remade/universal-modder |
| VS Code / Copilot | enable chat.plugins.enabled, run Chat: Install Plugin From Source, paste the repo URL |
| Cursor | Cursor Marketplace, or clone the repo |
| OpenCode | clone and run opencode inside it |
| Any Agent Skills agent | npx skills add https://github.com/rehan-remade/universal-modder |
Detailed walkthrough: universal-modder.dev/install · Claude Code deep-dive: universal-modder.dev/claude-code
Create a key at https://fal.ai/dashboard/keys, then:
export FAL_KEY="your-key" # macOS / Linux / WSL
setx FAL_KEY "your-key" # Windows (open a new terminal after)No key? um comfy makes images with a local ComfyUI server. Prices (checked October 2026): ~$0.211 per high-quality sprite, $0.08 per image, $0.25–0.35 per 3D model, $0.002 per second of SFX. Cost calculator.
What engine is my copy of Terraria, has anyone modded it before, and what route would you take? Don't change anything yet.
Add one boomerang that bounces between enemies four times before returning. Placeholder sprite first, then a fal sprite once it works in game.
Good first games: Terraria (tModLoader), Stardew Valley (SMAPI), Minecraft (Fabric), Unity games with BepInEx. Game library.
| Error | Fix |
|---|---|
| Git/SSH error adding the marketplace | git config --global url."https://github.com/".insteadOf git@github.com: |
| Skills don't appear | /reload-plugins or restart the agent |
um: command not found |
open a new terminal, or uv tool update-shell |
pip install universal-modder fails |
it's not on PyPI; use the git+https:// form above |
| fal key missing | set FAL_KEY, then restart the agent |
um win refuses to run |
game control is Windows / WSL only |
Is Universal Modder free? Yes, it's MIT licensed. Your agent plan and fal assets are billed separately.
Does it work on Mac or Linux? Install, knowledge base, asset tools and backups do. Driving and recording the game (um win) is Windows or WSL only.
Will I get banned? Not if you keep to games you own, offline or on servers you host. It refuses anti-cheat bypasses and cheats against other players. Safety rules.
Is it the same as universal-game-modder? No. That's an unrelated npm MCP server. Comparison.
Can it mod Minecraft / GTA 5 / Palworld? Minecraft and GTA V have working field notes; Palworld has none yet. See Minecraft, GTA 5 and Palworld.
Unofficial and community-maintained; not affiliated with the universal-modder maintainers. Guide text CC BY 4.0. Main site: universal-modder.dev · Google Sites: sites.google.com/view/universal-modder