Skills, tools and a shared knowledge base that let any AI coding agent mod almost any PC game you own.
The agent finds the game, works out the engine and the route, reads the real code, builds the mod, makes art, 3D and sound
with fal, tests it in the running game, cuts the video, and writes down what it learned for the next agent.
Coming next: the mod hub at universalmodder.com. Publish your mods, remix other people's, and make new ones.
Share what you make, get help, and follow along:
Install
Pick your agent. Each gets the same skills (Agent Skills format), the fal MCP server, and the um CLI.
Enable chat.plugins.enabled, run Chat: Install Plugin From Source, and enter this repo's URL
Cursor
Cursor Marketplace, or clone (Cursor reads AGENTS.md and .cursor/mcp.json)
OpenCode
Clone and run opencode inside it (opencode.json adds the skills and the fal MCP server) or, on OpenCode 2, opencode plugin add 'github:rehan-remade/universal-modder#main::path:plugins/opencode' (the um tool and fal MCP; add the skills with Skills only)
git clone https://github.com/rehan-remade/universal-modder and start your agent inside it
Inside a clone, each agent finds the skills where it looks for them: .agents/skills (Codex, Gemini CLI,
Copilot, Cursor, OpenCode) and .claude/skills (Claude Code) are copies of skills/. Instructions are in
AGENTS.md, which CLAUDE.md and GEMINI.md point to. MCP config is in .mcp.json, .codex/config.toml,
.cursor/mcp.json, .vscode/mcp.json and opencode.json (which also points OpenCode at skills/).
Without a clone, OpenCode 2 installs the plugin in plugins/opencode/ with opencode plugin add: one
um_run tool that passes its arguments straight to the CLI and runs um from PATH (see below), plus the
fal MCP server when FAL_KEY is set and none is configured. A clone doesn't need it. See
plugins/opencode/README.md.
The um CLI. The Claude Code plugin puts it on PATH (its SessionStart hook), and so does a clone opened in
Claude Code (.claude/settings.json); in a clone with another agent, export PATH="$PWD/bin:$PATH". Other
agents' plugin installs (Codex, Cursor, Gemini CLI, OpenCode) don't, so install it once:
For assets, get a fal API key. It powers both the fal MCP server and
um fal. Rather than exporting it from a shell profile or a .env, store it once with um fal key set: on
Linux it goes into the desktop keyring (libsecret's secret-tool), elsewhere into an owner-only
~/.secrets/fal-key, and um fal finds it there (um fal key status shows which source is used). FAL_KEY
in the environment still works and wins. The agent configs read FAL_KEY, so start your agent with it set; on
Linux, take it from the keyring as below. With no key, fal's OAuth endpoint https://mcp.fal.ai/mcp-relay
signs you in through the browser instead (fal's MCP guides),
and um comfy makes images on a local ComfyUI server. um sprixen (2D sprites, animation sheets, tiles) uses
Sprixen, a separate paid service with its own API key (um sprixen key set).
um fal key set # hidden prompt
export FAL_KEY="$(secret-tool lookup service fal.ai key api)" # Linux: before starting the agent
You also need Git, Python 3.10+ and ffmpeg. uv is recommended. Blender is needed for 3D → sprite renders.
Windows games are driven natively or from WSL.
Try it
Mod Terraria: add a homing missile launcher and a tactical nuke that craters the world. Make the sprites with fal.
Make a new civilization for Age of Empires II with a unique unit rendered from 3D.
Put real Minecraft inside GTA V story mode. Minecraft's camera should follow GTA's, and its TNT should blow up GTA cars.
Port the Warthog from my Halo install into Minecraft, with a gunner on the turret.
What engine is C:\Games\Foo, and has anyone modded it before?
The agent starts with the mod-any-game skill and runs the same loop every time:
search the knowledge base;
recon, then pick a route;
set up a safe lab (saves backed up);
read the actual code;
build one working slice;
generate assets;
verify in the real game;
record;
package;
write a field note for the next agent.
A knowledge base that AIs write for AIs
knowledge/ holds field notes: how specific games were actually modded, decompiled and
reverse-engineered. Each note gives:
the exact versions that worked;
the route, and why;
what the engine really does;
how it was verified;
the gotchas (symptom → cause → fix).
Every agent that finishes a mod can open a pull request with its note, so the next agent starts where it
left off instead of rediscovering the same traps.
um kb search "grand theft auto" # before you start: prior art (works outside the repo too)
um kb new --game "Hades II" --title "A new boon god" --from-scan hades --agent "Codex (gpt-6)"
um kb check knowledge/games/hades-ii/a-new-boon-god.md
um kb pr knowledge/games/hades-ii/a-new-boon-god.md --yes # after your human says OK: branch, push, PR
Browse knowledge/INDEX.md. Every game is welcome. Contribution rules, for humans and
AIs, are in CONTRIBUTING.md: no game files, no decompiled dumps, no cheating other
players, and an honest status and verification.
Open-web research that survives dead forums: Wayback/archive.today, GitHub/code and Nexus/Workshop/Thunderstore APIs, Reddit/YouTube, login-gated handoff, screenshots as evidence
ILSpy / Cpp2IL / Vineflower / Ghidra and IDA over MCP / Cheat Engine / Frida / RenderDoc; reverse-engineer a file format and prove it with a round trip
Port an existing mod to a newer version or loader without drift: one pinned source, a private decompile, data extracted by script, unit-by-unit tests, audits by layer, resumable status docs, and a Forge 1.7.10 → Fabric 1.20.1 mapping table
Search the knowledge base, write your own note, open the PR
Agents (agents/, subagent files with name + description frontmatter): a three-agent team for mods
that take days. Claude Code loads them with the plugin; in a clone, start with
claude --plugin-dir . --agent mod-orchestrator. Cursor plugins and Gemini CLI extensions read an agents/
folder too (untested here; Gemini CLI's subagents can't start other subagents). Three agents use several
times the tokens of one, so keep it for long mods. What worked for one user: the orchestrator on Fable 5.1 at
medium effort, the game worker on Sonnet 5.5 at medium, and the offline worker on Opus 5.5 at high. Any agent can
read the files as role briefs.
The supervisor. Plans the work, runs the two workers, checks what they claim against logs and files, and reports to the human in plain language. Start it as the main session: claude --agent mod-orchestrator
Never touches the game: studies SDK data, dumps and other mods, designs features, writes generators and patches, tests them against stubs, and hands over the exact live probes to run
The um CLI (Python). Every command has --help with examples.
Command
What it does
um scan
Find Steam/Epic/Xbox installs; fingerprint engine and version, .NET vs native, anti-cheat, installed loaders, save folders, ranked routes
um fal
sprite, image, edit, rmbg, pixelate, upscale, texture, pbr, model3d, rig, sfx, music, voice, video, run, search, schema, price. Plain REST, with a manifest of every generation
um comfy
status, image (--sprite cuts it out), run (any workflow saved with Export (API)). Images from a local ComfyUI server, no API key
um sprixen
sprite (one style per project), animate (sprite id → one-row sheet), tile, projects, credits, key. 2D art from Sprixen's paid API, with a manifest of every generation
A Fabric mod and a ScriptHookV + ReShade add-on exchange camera, ground and events over a local
WebSocket.
Minecraft's colour + depth are depth-composited into GTA's frame.
Minecraft TNT, arrows and fireworks become GTA explosions and bullets, and Minecraft mobs fight the
police.
Each has a field note with every non-obvious lesson: knowledge/INDEX.md.
Rules it follows
Any game you own: single-player, multiplayer, or servers you host. It refuses to inject into online
games with anti-cheat, write cheats against other players, or bypass anti-cheat, DRM or ownership checks.
It never ships game files or decompiled code. Mods ship as code, your own assets, patches or
converters.
It backs up before touching saves, and kills processes by PID only.
It asks before driving your mouse and keyboard, installing loaders into game folders, or publishing,
PRs included.
Show it off in the Discord, and put the badge on your mod's page:
[](https://github.com/rehan-remade/universal-modder)
Use made-with-light.svg on a light page.
Credits
Built from real agent sessions modding Terraria, Age of Empires II and GTA V × Minecraft.
Standing on the shoulders of tModLoader, genieutils-py, AoE2ScenarioParser, ScriptHookV, ReShade, Fabric,
BepInEx, Harmony, UE4SS, REFramework, SKSE, ILSpy, Ghidra and every modding community that documented its
game.
The engine playbooks also draw on the September 2026 wave of AI-built mods, and on how their creators
explained them in public.
MIT licensed. Brand type: Geist Pixel, Sometype Mono and Instrument Sans. Video titles: Space Grotesk and JetBrains Mono. All under the SIL OFL.
Star history
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这是什么？Universal Modder 为 Claude Code（以及其他 AI 编程代理）提供一套 Agent Skills、一个名为 um 的 CLI 和一个 fal MCP 服务器，让代理能够对几乎任何你拥有的 PC 游戏进行查找、逆向工程和修改（mod），然后生成美术、3D 和音频素材，在游戏中测试 mod，并录制展示视频。
这是独立应用，还是接入我的编程代理？它不是独立应用，而是一个插件/技能包：同样的 Agent Skills、fal MCP 服务器和 um CLI 会安装到你已经在用的任何代理中（Claude Code、Codex、Gemini CLI、Copilot、Cursor、OpenCode）。
在 Claude Code 中怎么安装它？在 Claude Code 中运行 '/plugin marketplace add rehan-remade/universal-modder'，然后运行 '/plugin install universal-modder@universal-modder'。其他代理（Codex、Gemini CLI、Cursor、OpenCode、Copilot）在 README 中有各自的一行安装命令，你也可以直接 git clone 仓库并在其中启动你的代理。
除了编程代理，我还需要安装什么？你需要 Git、Python 3.10+ 和 ffmpeg（推荐使用 uv），如果想要 3D 模型转游戏精灵渲染，还需要 Blender。fal API 密钥用于驱动 fal MCP 服务器和 um fal 来生成 AI 美术/音频/3D；没有密钥的话，可以改用 um comfy 对接本地 ComfyUI 服务器。
它会修改联机游戏或编写作弊器吗？不会。它只处理你拥有的游戏，并且拒绝向受反作弊保护的联机游戏注入代码、编写针对其他玩家的作弊器，或绕过反作弊、DRM 或所有权检查。最终生成的 mod 也绝不包含游戏文件或反编译代码。
修改游戏必须用 Windows 电脑吗？Windows 游戏可以在 Windows 上原生驱动，也可以从 WSL 驱动，窗口捕获/输入自动化（um win）以两个免构建的 PowerShell/C# 工具形式提供，因此最重的自动化功能面向 Windows。技能和 CLI 本身是纯 Python，可以随你的编程代理所在的任何操作系统一起使用。
Universal Modder 为 Claude Code（以及其他 AI 编程代理）提供一套 Agent Skills、一个名为 um 的 CLI 和一个 fal MCP 服务器，让代理能够对几乎任何你拥有的 PC 游戏进行查找、逆向工程和修改（mod），然后生成美术、3D 和音频素材，在游戏中测试 mod，并录制展示视频。