Game Mod

game-mod — mods, patches, and total conversions for a specific game

This sub-skill stands up a game-mod project: a change to an existing game, packaged for its mod loader and deployed into a real install. It mirrors common setups — e.g. Elden Ring (Smithbox + Seamless Co-op on Linux; the row-name-strip gotcha; specific deploy paths) and the Gothic 1 Remake (UE5.4, Proton-launched, UE4SS loader — which silently fails to load unless WINEDLLOVERRIDES="dwmapi=n,b" is set). Linux + Proton + loader quirks are first-class concerns, and backing up saves and game files before any deploy is non-negotiable.

What this sub-skill is for

A mod for one named game + engine: balance tweaks, retextures, new items/quests, scripts, or a total conversion — distributed via that game's mod loader and dropped into the game's mod folder. Not for standalone games (those are their own project), not for engine/tooling work unrelated to a shipping game. It composes with cli-tool if the mod needs a build/deploy script, and with content-writing if it ships substantial lore/dialogue.

Mandatory grill-questions (fold into the Definition of Ready)

Lock these before touching any game file:

• Game + version + engine — exact title, build/patch number, engine (e.g. UE5.4, FromSoft formats). Mods are version-fragile; pin the version now.
• Mod loader / toolchain — which loader, and is it installed? (UE4SS, Smithbox, BepInEx, Reframework, Vortex/MO2, native). Default to the loader the user already runs for this game.
• Platform & launcher — Linux/Proton (the common default here), native Linux, or Windows? Which Proton/GE build? Record the prefix path.
• Loader gotchas — capture them explicitly: UE4SS needs WINEDLLOVERRIDES="dwmapi=n,b" or it won't load; Smithbox strips row names on save (re-add them); per-game load order rules. Write these into CLAUDE.md so no session rediscovers them.
• Deploy path — the exact game/mods directory inside the Proton prefix or native install. Get the real path, do not guess.
• What the mod does — scope in/out — the concrete change set for v1 and what's explicitly out.
• Online/multiplayer & anti-cheat — does it touch online play (e.g. Seamless Co-op)? Flag ban/anti-cheat risk and EAC-off requirements up front.
• Backup plan — confirm saves + original game files (and a clean prefix snapshot) are backed up before the first deploy. This is a gate, not a suggestion.
• Distribution — private/personal only, or shared (Nexus/GitHub release)? Drives licensing and asset-provenance care.

Project sub-agents to generate (into <project>/.claude/agents/)

• mod-deployer (delegate-by-default) — backs up saves + game files first, then builds and copies the mod into the real deploy path with the correct load order; sets/records required env (e.g. WINEDLLOVERRIDES); never deploys without a verified backup.
• compat-checker (delegate-by-default) — validates engine/loader/Proton compatibility, knows the per-game gotchas (UE4SS dwmapi override, Smithbox row-name strip), checks load-order conflicts with other installed mods, and flags game-version mismatches.
• asset-editor — handles the game-specific formats (param/regulation files, textures, scripts) safely, preserving names/IDs the tooling tends to drop.
• Plus the kit defaults: reviewer (diff/PR) and verifier (here = launches the game and confirms the mod actually loads in-game without crashing).

Tools / CLIs / MCP / skills needed

Check in environment-readiness; offer install, never auto-install:

• The game's mod loader + editor — UE4SS, Smithbox, BepInEx, Reframework, etc. Verify it's installed and on the right version for the game build.
• Proton / Wine tooling — protontricks, the GE-Proton build, the prefix path; the WINEDLLOVERRIDES env for UE4SS-class loaders. Confirm the launcher (Steam/Heroic) injects it.
• Backup tooling — rsync/tar snapshots of saves + game dir + prefix before deploy; a documented restore command.
• Format tools — texture/converter/unpacker CLIs specific to the engine (e.g. UE pak tools, FromSoft format tools). Flag anything missing.
• CHAIN global skills: deep-research (find the exact loader/gotcha for an unfamiliar game), verify (launch the game to confirm load), code-review, cli-anything (wrap a GUI mod tool into a scriptable CLI), doc-coauthoring (install/usage README), update-config (permissions/hooks for the deploy + env commands).

File / asset nudges (on top of the base set)

Beyond CLAUDE.md, PROJEKT_.md, TASKS.md, DONE.md, README, .claude/:

• mod/ — the mod source/assets (scripts, params, textures), engine-organised.
• deploy/ — a deploy script + an env.sh carrying the required overrides (e.g. WINEDLLOVERRIDES), and the recorded real deploy path.
• backups/ — .gitignored save/game-file snapshots + a restore script; an BACKUP.md documenting what's backed up and how to roll back.
• GOTCHAS.md — the per-game loader quirks (UE4SS dwmapi, Smithbox row-name strip, load order), so they're never rediscovered the hard way.
• INSTALL.md — install the loader, set env, deploy, and uninstall/restore steps for the user.

Stack defaults & done-bar

Defaults: Linux + Proton (GE) launch, the user's existing loader for that game, env overrides recorded in deploy/env.sh, mandatory pre-deploy backup, mod source versioned in git, big binary assets .gitignored unless distribution requires them. Pin the game build version everywhere. Done-bar (all true): original saves + game files are backed up with a tested restore; the mod loads in-game on the real install without crashing, verified by actually launching the game; the intended change is observable in-game; no anti-cheat/online violation if online play is in scope; GOTCHAS.md + INSTALL.md are accurate enough for a clean re-deploy from scratch.

Guardrails

• Back up before every deploy — saves, original game files, and (ideally) a prefix snapshot. Never write into a game install without a verified, restorable backup. This is the top rule.
• Honesty about "it works": don't claim the mod loads until verifier has launched the game and seen it load. Report crashes, missing-load (silent UE4SS failure), and version mismatches plainly instead of assuming success.
• Anti-cheat / ban risk: if the mod touches online play, state the ban/EAC risk explicitly and do not enable online unless the user confirms; mirror the Seamless Co-op caution.
• Respect the loader's quirks — set WINEDLLOVERRIDES for UE4SS, re-add Smithbox row names, honour load order. Record each gotcha in GOTCHAS.md.
• Asset provenance & licensing — for shared mods, verify you may redistribute every asset; don't ship copyrighted game assets you can't redistribute. Record provenance.
• No emojis in any tool/UI output the mod surfaces (user's standing rule).
• Commits under the user's own name only (Skryx-L-A); never add Claude as a co-author.