What is Universal Modder?

Last updated: 2026-10-16

Universal Modder is an open-source (MIT license) toolkit that lets AI coding agents — Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode, per its README — create mods for PC games you own.

It ships as Agent Skills plus a Python CLI called um and an MCP server for the fal asset-generation service, and it follows a fixed loop: search prior field notes, recon the game, set up a safe lab with saves backed up, read the game code, build one working slice, generate assets, verify in the running game, then record a field note.

Details

The toolkit ships 12 engine playbooks covering Unity, Unreal, .NET/XNA (Terraria, Stardew Valley, Celeste), Godot, Source 1/2, Bethesda titles, Minecraft, AoE2/Genie, RE Engine / FromSoft / GTA / Cyberpunk / BG3, native C++, indie engines and retro decompilations.

Treat "mod almost any PC game" as the project's ambition: real coverage depends on the engine playbook and on field notes from previous mods, so check the knowledge base for your specific game first.

FAQ

Is Universal Modder safe to use?
The project states hard limits itself: it refuses to inject into online games with anti-cheat, never ships game files or decompiled code, backs up saves before touching them, and asks before driving your mouse and keyboard, installing loaders, or publishing anything.

Sources

This is an independent guide written from public documentation (the project's GitHub README and LICENSE). We are not affiliated with the universal-modder project or its authors, and this is not the official website. Product details change — the official GitHub repository is the source of truth.