cranebeaker/coop-anything

Co‑op Anything – Turn a single‑player game into a co‑op experience with AI agents

What it is – A framework that lets a large‑language‑model‑based coding assistant (Claude, Codex, Gemini, Cursor, …) turn any PC game you own into a multiplayer‑ready title. The agent reads the repository, discovers the game’s engine, either revives an existing co‑op mod or builds a new one from scratch, runs automated bot‑based tests, and finally packages the result so friends can join through Steam’s free Spacewar relay server – no port‑forwarding required.

How it works

• Two pathways – Path 1 fixes or finishes an already‑existing co‑op mod; Path 2 starts from zero, reverse‑engineering the game and adding networking hooks.
• Agent‑driven workflow – Skills are defined in .agents/skills (or .claude/skills). The agent follows the playbooks in the playbook/ folder, which cover research, reverse‑engineering, networking, automated QA, etc.
• MCP server – The Co‑op Anything MCP (tools/mcp/coop_mcp.py) lets any agent discover a game’s engine, read the appropriate playbook, and validate contributions.
• Testing & delivery – Real game clients are launched with bots to verify synchronization, then the mod is packaged for a one‑click Steam install that uses Valve’s free Spacewar app as a relay.

What you can co‑op – The repo lists typical approaches per engine family (Unreal, Source, id Tech, Bethesda’s Creation Engine, Unity, RE Engine, decompiled ports, console emulators, etc.) and the tooling the agent will employ (script extenders, DLL hooks, Harmony patches, decompilation tools like Ghidra/REA, mod loaders such as BepInEx, UE4SS, etc.).

Games already supported –

Game	What was done	Release
Deus Ex (2000)	Revived HX co‑op mod, added Steam relay, automated tests	✅
Dungeon Keeper (1997)	Shared‑keeper co‑op on KeeperFX, Steam relay	✅
S.T.A.L.K.E.R. – Shadow of Chernobyl / Clear Sky	Fixes for co‑op, Clear Sky in progress	✅
Fallout: New Vegas	Story‑co‑op (shared quests, karma, reputation)	✅
Zelda: Ocarina of Time	Sync fixes for Ship of Harkinian fork	✅

Getting started – Tell your coding agent something like:

Read https://github.com/cranebeaker/coop-anything and follow AGENTS.md.
I want to play <game> in co‑op with my friends.

The agent then uses the MCP, the appropriate skill set, and the playbooks to produce a pull request with the new or fixed mod.

Community & contribution – Anyone can run an agent, open a draft PR, and have humans review it. A Discord server and extensive documentation (playbooks, tool lists, engine‑family guides) support collaboration. The project is MIT‑licensed and explicitly avoids distributing any game assets.

Who it’s for – Players who own a single‑player PC game and want to play together without writing code themselves, and developers who want to harness LLM‑driven agents to automate the heavy lifting of reverse‑engineering and mod creation.