Point your AI agent at a single-player game, get co-op

What it does You tell your agent (Claude Code, Codex, Cursor, etc.) which single-player game you want to play with friends, and it does the whole modding job: research what co-op work already exists, reverse engineer the game if needed, build or fix the mod, test it with bots driving real game clients, and package it for one-click install with Steam relay networking — no port forwarding. It ships as an MCP server plus a playbook of skills, and every agent’s findings flow back into the repo as pull requests, so the next person’s agent starts where yours stopped.

The interesting bit The two-path design is smart: most beloved games already have a half-finished, abandoned co-op mod, so the agent’s first job is archaeology — find the last build, mine bug reports from forums and Discord, and revive it. The genuinely novel part is the QA tooling: a chaos relay that injects lag and packet loss, a flight recorder that pinpoints the first desync across machines, and a fuzzer with invariant oracles (no double-applied actions, one owner per NPC, nothing stale). That’s real distributed-systems discipline applied to game mods.

Key highlights

• Works across engine families: Unity, Unreal, Bethesda, id Tech, decomp projects, and even console games via emulator memory-sync or recompiled PC ports
• Ships a directory of 230+ co-op mods with honest QA levels — untested, player reports, automated tests, or verified playthrough
• Real shipped results: Deus Ex co-op revived, Ocarina of Time fully synced, Fallout: New Vegas story co-op in progress
• Split-screen support on one PC via Nucleus Co-op (Windows) and PartyDeck (Linux/Steam Deck)
• No coding knowledge required — the agent asks before installing anything or touching your accounts

Caveats

• Success depends heavily on the game: a closed binary with no existing mod is flagged as “the hardest path” requiring full reverse engineering
• The README is a pitch for a workflow, not a finished product — many listed games are community projects in progress, not done deals

Verdict If you’ve ever wished a dead single-player game had co-op and you have a coding agent subscription, this is the most ambitious use of agent labor pooling you’ll find. If you want a polished, guaranteed-working mod for your specific game today, check the directory’s QA level first and temper expectations.