'Co-op Anything': An Open-Source Framework for Turning Single-Player Games into Co-op with AI Agents
An open-source framework enabling AI coding agents to reverse engineer single-player PC games into multiplayer co-op modes with automated netcode verification.
Image source: Co-op Anything / https://coopanything.app/
AI coding agents such as Claude Code, Codex, and Cursor can now reverse engineer single-player PC games and convert them into multiplayer co-op modes using Co-op Anything (cranebeaker/coop-anything, MIT License), an open-source framework and playbook.
Moving beyond one-off mod creation, Co-op Anything provides dedicated agent skillsets and tooling so that AI agents can autonomously comprehend complex game binaries and engine structures, write network synchronization code, and execute real-time verification.
Dedicated Agent Skillsets and Reverse Engineering Tooling
Co-op Anything provides integrated workspaces and tooling designed to deploy AI coding agents directly into game modding tasks.
- Dedicated Skillsets and MCP Integration: Via the
.agents/skillsdirectory, it supports game engine detection, existing mod discovery, andAGENTS.md-driven guidance, tightly integrated with the REA (Reverse Engineering Anything) MCP for binary analysis. - Support for Multiple Game Engines: Includes playbooks guiding reverse engineering and netcode implementation across Unreal, Source, Unity, and Creation Engine.
- Tracked Mod Projects: Tracks over 230 co-op mod projects—including Deus Ex, Fallout: New Vegas, and Zelda: Ocarina of Time—to train agents on verified architecture patterns.
Network Synchronization Automated Verification and Testing Tools
To address netcode synchronization and desync issues, Co-op Anything provides various in-house testing tools for pre-verifying synchronization without launching game clients directly.
- chaos: Simulates UDP latency and packet loss to test stability under poor network conditions.
- flight: Asynchronous desync tracker capturing state discrepancies between clients in real time.
- fuzz: Multi-player fuzzer testing edge cases under multi-connection environments.
- ownership: NPC permission management library preventing AI and game object ownership conflicts.
Packaging and Distribution Workflow
Finished mods use Steam Relay Networking for packaging, allowing players to install and connect with friends easily without complex port forwarding configurations.
However, modding difficulty varies widely depending on engine type and existing mod support. Achieving flawless synchronization requires in-house bot and scenario testing. Binary analysis and hooking also require proper configuration of external tools such as Ghidra, REA, and Script Extenders.