What is cities-skylines-2-mcp?

CS2MCP is an MCP server that lets Claude, or any other MCP compatible AI client, control a running copy of the city building game Cities Skylines II. MCP is a protocol that lets AI assistants call tools, and this project exposes 44 of them, letting an AI observe the city, build roads and buildings, paint residential, commercial, or industrial zones, adjust taxes and budgets, and control the pace of the simulation, including pausing it or running it forward by a set number of in game hours. The system has two parts. A mod written in C# runs inside the game itself and starts a small local web server that only accepts connections from the same machine. It reads and changes the game's data on the simulation's own main thread, and it builds or demolishes things using the game's normal construction and bulldozer systems rather than editing data directly, so changes stay valid within the game's rules. A separate MCP server, written in TypeScript and run with Node.js, translates tool calls from Claude into requests sent to that in game web server. To use it you need Windows, Cities Skylines II from Steam, the .NET SDK version 8 or newer to build the mod, and Node.js 18 or newer to run the MCP server. Building the mod copies it into the game's mods folder automatically, and it loads the next time the game starts. The MCP server can then be registered with Claude Code or Claude Desktop by pointing at its built file. Once connected, and with a save loaded in the game, you can ask Claude things like how a city's finances look, to zone a residential area near a river, or to build a road connecting an industrial district to the highway, and it will read the current state and make the change through the same tools a player would use. Screenshots can be taken so the AI can see the current view alongside the raw data. The README notes some current limits: buying new map tiles, planning transit lines, and reshaping terrain are not supported yet and are planned for a future version, and roads can only connect at existing segment endpoints rather than merging smoothly in the middle of a road.