Reference

The 11 Universal Modder skills

Skills are instructions your agent loads when a task matches. One orchestrator, ten specialists, and twelve engine playbooks behind them.

01 · The orchestrator

mod-any-game

Takes an idea to working in the real game and recorded. Runs the 10-step loop, enforces the hard safety rules, and holds the 12 engine playbooks and case studies.

Loads when: Any modding request: “add a nuke to Terraria”, “can I mod this game?”, “put Minecraft inside X”.

references/engines/*.md, case-studies.md, safety.md

02 · Before any code

game-recon

Finds the install, engine and version, managed vs native code, anti-cheat, loaders already present, save and config folders, and the community route. Writes MODDING_PLAN.md.

Loads when: “What engine is this?”, “how do people mod X?”, the start of every task.

03 · Open-web research

game-research-websearch

Archive-aware research: Wayback Machine and archive.today for dead forums (XeNTaX, Zenhax), GitHub code search, Nexus / Workshop / Thunderstore APIs, Reddit, YouTube transcripts, with snapshots kept as evidence.

Loads when: A tool link is dead, a forum is login-gated, or a field note needs sources.

04 · Read the real code

reverse-engineering

Decompiles .NET/Mono (ILSpy), IL2CPP (Cpp2IL, Il2CppDumper), Java (Vineflower) and native code (Ghidra, IDA over MCP); reads live memory (Cheat Engine, Frida, x64dbg); finds render passes (RenderDoc); proves a file format with a round trip.

Loads when: “How does the boss AI work?”, “what format is this .pak?”, “where is the player position?”

05 · Art, 3D and audio

fal-assets

Sprites with real transparency, consistent variants and animation frames, pixel art, seamless textures, PBR maps, image-to-3D, remeshing, auto-rigging, SFX, music, voice and cutscene video through the fal MCP or um fal.

Loads when: A mod needs new art, sound or models.

06 · Engine-exact frames

asset-pipeline

Cutouts, nearest-neighbour fitting to frame sizes, palettes, sheets and strips, team-colour masks, seamless textures, and 3D → 8/16-heading sprites rendered from the game's camera in Blender.

Loads when: After generating art, or when asked for sprite sheets, isometric units or icons.

07 · Test in the real game

game-automation

Launch via Steam or exe, fixed-size windowed mode, GPU-safe screenshots, safe clicks and keys, crash-reporter cleanup, kill by PID, logs, scripted test scenes and an in-game JSON bridge. Windows-first, also from WSL.

Loads when: A mod must be verified in game, or a repeatable demo scene is needed.

08 · The clip

showcase-video

Records the window with only the game's audio, picks moments from contact sheets, and cuts a styled video from an EDL: titles, credits, transitions, music, watermark.

Loads when: A demo, trailer or montage for X or YouTube.

09 · Game inside a game

mashup-mods

Passthrough mods (two games running and exchanging state, rendering and collision), content ports, decompiled games as libraries, and clean reimplementations that read your own game files.

Loads when: Combining two games, or bringing an enemy, mechanic or world from one into another.

references/mashup-cases.md

10 · Ship it

publish-mod

Pre-release lint, README and install steps, credits and AI disclosure, versioning, uploads (Nexus Mods, Steam Workshop, Thunderstore, mod.io, GitHub releases) and the post.

Loads when: Ship, share, upload or release.

11 · Teach the next agent

share-field-notes

Searches the knowledge base before work starts, and at the end writes a field note (versions, route, engine facts, verification, gotchas) and opens a PR with your OK.

Loads when: “Has anyone modded X?”, when stuck on an engine quirk, and at the end of every session.

The 12 engine playbooks

Inside mod-any-game/references/engines/. um scan tells the agent which one to read.

PlaybookCoversTypical tools
unity.mdUnity (Mono & IL2CPP)BepInEx, MelonLoader, Harmony
unreal.mdUnreal Engine 4 / 5UE4SS, pak mods, UEVR
dotnet-xna.md.NET / XNA / FNATerraria, Stardew Valley, Celeste
godot.mdGodotPCK files, GDScript
source.mdSource 1 / 2Valve games, VPK, VAC rules
bethesda.mdBethesda (Creation)SKSE, ESP/ESM/ESL plugins
minecraft.mdMinecraftFabric, NeoForge, Forge, Bedrock add-ons
genie-aoe2.mdGenie / AoE2Data mods, .sld sprites, scenarios
big-frameworks.mdBig frameworksRE Engine, FromSoft, GTA, Cyberpunk, BG3
native.mdNative C++Hooks, proxy DLLs, ASI loaders
misc-engines.mdIndie enginesGameMaker, RPG Maker, Ren'Py, Paradox, Doom, HTML5, LÖVE, Java
retro-decomp.mdRetro & consoleDecomps, recomps, emulators

The skills call the um CLI for anything mechanical, and lean on the knowledge base for prior art.

Frequently asked questions

What format are the skills in?

The open Agent Skills format: each skill is a folder with a SKILL.md (front matter with a name and description, then instructions) and optional reference files. Any agent that supports Agent Skills can load them.

Do I have to call the skills myself?

No. Agents load a skill when your request matches its description. In Claude Code you can force one with /universal-modder:<skill-name>.

Can I use one skill on its own?

Yes. For example fal-assets and asset-pipeline are useful for any game project, not only mods. Install with npx skills add and pick the ones you want.