FactoMCP

An MCP server that lets Claude play Factorio. Claude can walk around, mine resources, place buildings, manage research, and build out a factory — all through natural language.

Fair warning: It’s slow, makes spatial reasoning mistakes, and burns through tokens fast. But it works, and it’s genuinely fun to watch.

How it works

The server connects to a running Factorio instance via RCON and exposes a set of MCP tools that execute Lua commands in the game. Claude uses these tools to perceive the game state and take actions as the player.

Requirements

• Factorio (tested on 2.0)
• Python 3.10+
• Claude Code (or any MCP-compatible client)
• The server must run on the same machine as Factorio

Setup

1. Configure RCON in Factorio

RCON only works in multiplayer mode. You need to either:

Option A — start from the command line:

factorio --start-server mysave.zip --rcon-port 25575 --rcon-password CHANGE_ME

Option B — start a local multiplayer game and set RCON in config.ini:

[rcon]
rcon-port=25575
rcon-password=CHANGE_ME

Then start Factorio normally and open a multiplayer (LAN) game.

Option C — configure via the in-game GUI:

Factorio supports a number of hidden configuration options that are not normally shown in the GUI. They can be accessed by holding CTRL + ALT when clicking the “Settings” button in the pause menu, which will cause a new button labeled “The rest” to appear. The RCON port and password settings are in there.

2. Install the server

git clone https://github.com/WidAmi/FactoMCP.git
cd FactoMCP
python -m venv .venv
source .venv/bin/activate   # Windows: .venv\Scripts\activate
pip install -r requirements.txt

3. Configure the MCP connection

The repo includes a mcp.json.example you can use as a starting point. Copy it to .mcp.json and edit it to match your setup:

{
  "mcpServers": {
    "factomcp": {
      "type": "stdio",
      "command": "/path/to/FactoMCP/.venv/bin/python",
      "args": ["/path/to/FactoMCP/server.py"],
      "env": {
        "RCON_HOST": "127.0.0.1",
        "RCON_PORT": "25575",
        "RCON_PASSWORD": "CHANGE_ME"
      }
    }
  }
}

Or set the environment variables manually and run:

RCON_PASSWORD=CHANGE_ME python server.py

4. Connect Claude Code

From the FactoMCP directory, start Claude Code:

claude

Claude Code will automatically pick up .mcp.json. You can verify the server connected with /mcp.

5. Start playing

With Factorio running and Claude Code connected, just tell Claude what to do:

Take a look around and find the ore patches
Build a basic iron smelting setup near the iron ore
Set up automated coal mining to keep the furnaces running

Environment variables