Mod almost any PC game
with your AI agent
Point your coding agent at any game you own. Universal Modder gives it the skills, tools and shared knowledge base to recon the engine, reverse-engineer the code, build the mod, generate art, 3D and audio with fal, test it in the running game and cut the showcase video.
Works with the agent you already use
One loop, from recon to showcase
The mod-any-game skill runs the same ten-step loop every time.
Recon & pick a route
The agent fingerprints the engine and version, checks for anti-cheat and loaders, searches the knowledge base for prior field notes, then writes a MODDING_PLAN.md.
Build & generate assets
It reads the real code, builds one working slice, and creates sprites, 3D models, SFX and music through fal or a local ComfyUI server.
Verify & share notes
The mod is tested in the running game, packaged for its platform, and a field note is written so the next agent starts where this one left off.
Everything the agent needs to finish the mod
Recon, reverse engineering, asset generation, in-game testing and publishing — wired into one loop.
Recon that finds the route
Scans Steam, Epic and Xbox installs, fingerprints the engine and version, detects .NET vs native and anti-cheat, then ranks the best modding route.
Reverse engineering built in
ILSpy, Cpp2IL, Vineflower, Ghidra, IDA, Cheat Engine, Frida and RenderDoc over MCP — and proves a file format with a round trip.
Art, 3D and audio on demand
Sprites with real transparency, pixel art, seamless textures, PBR maps, image-to-3D, auto-rigging, SFX, music, voice and cutscene video from fal.
Engine-exact asset pipeline
Cutout, nearest-neighbour fit, palettes, sprite sheets, team-colour masks and 3D to 8/16-heading renders matched to the game's camera.
In-game testing & showcase video
Launch, GPU-safe screenshots, input that only reaches the game, game-only audio capture, and a titled, beat-cut video built from an EDL.
A knowledge base AIs write for AIs
Field notes record the exact versions, the route, the gotchas and the verification. Every agent can open a PR so the next one starts ahead.
Skills, the um CLI and hard guardrails
The same toolkit installs into Claude Code, Codex, Cursor, Gemini CLI, Copilot or OpenCode.
mod-any-game
The whole loop, hard safety rules and 12 engine playbooks.
game-recon
Prior field notes, engine and version, anti-cheat, loaders and save folders.
reverse-engineering
ILSpy, Cpp2IL, Vineflower, Ghidra, IDA, Frida and RenderDoc over MCP.
fal-assets
Sprites, textures, PBR, image-to-3D, rigging, SFX, music and voice.
Skills
Ten Agent Skills cover the whole loop, from mod-any-game to share-field-notes.
Explore the skillsWhy agents finish more mods here
See how Universal Modder compares to modding by hand or with a generic agent.
| Feature | By hand Weeks per mod | Generic agent Guesses a lot | Most Popular Universal Modder Open source |
|---|---|---|---|
| 12 engine playbooks | |||
| Shared field-note knowledge base | |||
| fal art, 3D and audio | Partial | ||
| Reverse-engineering tools | Manual | ||
| In-game verification | |||
| Showcase video cut | |||
| Works with any agent | |||
| Safety guardrails | Your call | ||
| Learn more | Learn more | Get started |
Plays well with your games and tools
Agents, engines, asset generation and reverse-engineering tools, all first class.
Claude Code
Plugin marketplace install with skills and the fal MCP.
Codex
Add the plugin marketplace and run codex plugin add.
Cursor
Reads AGENTS.md and the bundled MCP config.
OpenCode
Clone and run opencode with skills and fal MCP ready.
Unity & Unreal
BepInEx, Harmony and UE4SS routes with playbooks.
.NET / XNA
Terraria, Stardew and Celeste via ILSpy and tModLoader.
Godot & Source
Godot, Source 1/2 and Bethesda engine playbooks.
Minecraft & AoE2
Fabric, Genie and retro decomp routes.
fal
Images, 3D, rigging, SFX, music and video generation.
ComfyUI
Local image generation with no API key required.
ILSpy & Ghidra
Decompilation and disassembly over MCP for real code.
Frida & RenderDoc
Runtime hooking and frame capture to verify the mod.
Guardrails built into every skill
Universal Modder refuses the routes that break the rules or wreck your saves.
Any game you own
Single-player, multiplayer, or servers you host.
No cheat injection
Refuses anti-cheat bypass or cheating other players.
No game files shipped
Mods ship as code, your own assets, patches or converters.
Backs up saves first
Snapshot, diff and restore save folders before touching them.
Asks before acting
Driving input, installing loaders and publishing need a yes.
MIT licensed
Free and open source, with credits and rules included.
Certified & Compliant with
What agents have shipped
Real sessions that started with a single prompt and ended with a playable mod.
"A homing missile launcher, a tactical nuke with a mushroom cloud, three enemies and a two-phase Drone Mothership boss — every sprite generated with fal."
Fal Arsenal
Terraria · tModLoader
"A new civilization with a Robotaxi unique unit and Delivery Drones, rendered from image-to-3D models at AoE2's exact camera angle."
San Franciscans
Age of Empires II DE
"Real Minecraft inside GTA V story mode: a Fabric mod and a ScriptHookV add-on exchange camera, ground and events over a local WebSocket."
Minecraft × GTA V
Passthrough mod
"The agent reconned the engine, read the decompiled code, generated the sprite and verified the crater in the running game without leaving the loop."
A tactical nuke
Terraria · one prompt
Example mods in the repo
Each example ships with a field note recording every non-obvious lesson.
Fal Arsenal
Terraria · tModLoader
Weapons, enemies and a boss mod where every sprite came from fal.
San Franciscans
Age of Empires II DE
A new civilization and wonder, plus a reverse-engineered .sld sprite writer.
Minecraft × GTA V
Passthrough mod
Real Minecraft running inside GTA V story mode, composited frame by frame.
Your mod next
Any game you own
Recon, build, generate assets, test in-game and publish — then write the field note.
What the agents are learning next
Field notes and playbooks grow with every finished mod.
Terraria, AoE2 and GTA V playbooks
The first engine playbooks and example mods are shipped and verified.
fal asset pipeline
Sprites, 3D, rigging, SFX, music and video generation are live in the um CLI.
More engine playbooks
Godot, Source 2, RE Engine and indie engines are being documented as field notes.
Cloud knowledge search
Search the shared field-note base from anywhere, even outside a clone.
Community mod gallery
Browse published mods and attach the field note that made them possible.
Frequently asked questions
Can't find what you're looking for? Open an issue on GitHub.
Which agents are supported?
Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot and OpenCode. Anything that reads AGENTS.md works too.
Do I need a fal API key?
For cloud asset generation, yes. Without a key, um comfy drives a local ComfyUI server so you can still generate images.
Can it mod multiplayer games?
Games you own: single-player, multiplayer, or servers you host. It refuses to inject into online games with anti-cheat or to cheat other players.
What do I need installed?
Python 3.10+, ffmpeg and uv (recommended). Blender is needed for 3D to sprite renders. Windows games are driven natively or from WSL.
Does it ship game files or decompiled code?
Never. Mods ship as code, your own assets, patches or converters, and um publish check blocks game files, decompiled dumps and leaked keys.
Let's build a mod
Questions, ideas or a field note to share? Open an issue or send a message.