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

Variable	Default	Description
RCON_HOST	127.0.0.1	Factorio RCON host
RCON_PORT	25575	Factorio RCON port
RCON_PASSWORD	CHANGE_ME	Factorio RCON password
FACTORIO_SCRIPT_OUTPUT	~/Library/Application Support/factorio/script-output	Path for screenshot output (Mac default)

Available tools

Navigation & perception

Tool	Description
get_player_position	Get the player's current coordinates
get_player_inventory	List everything in the player's inventory
scan_area	Summarize resources, entities, and structures within a radius
detail_area	Detailed tile-by-tile breakdown of a smaller area
walk_to	Walk the player to a position using legitimate movement

Mining & building

Tool	Description
mine_resource	Mine a resource or pick up an entity at a position
build_entity	Place an entity from inventory
build_line	Place a line of identical entities (belts, poles, etc.)
rotate_entity	Change the direction of a placed entity
load_entity	Put items from inventory into an entity (fuel, ingredients)
collect_from_entity	Take items out of an entity into inventory

Crafting & research

Tool	Description
craft	Queue a crafting recipe
get_crafting_queue	See what's currently being crafted
get_recipes	List unlocked recipes, with optional name filter
get_research_status	Check current research progress
get_available_technologies	List technologies that can be researched
set_research	Start researching a technology
set_recipe	Set the recipe for an assembling machine

Diagnostics

Tool	Description
get_entity_status	Check an entity's status, fuel, inventory, and health
diagnose_area	Identify idle or broken entities in an area
check_power_network	Inspect the power network around a location
check_fluid_connections	Check fluid connections for pipes and fluid entities
trace_connections	Trace belt/inserter connections from an entity
trace_fluid_network	Trace the fluid network from a pipe or entity

Misc

Tool	Description
run_lua	Execute arbitrary Lua in Factorio (use sparingly)
stop	Stop all player actions if something gets stuck
take_screenshot	Save a screenshot to Factorio's script-output directory
get_stats	Report call count and estimated token usage per tool for this session
clear_stats	Reset all usage statistics

A note on fairness

The tools in this server are designed to only do what a normal player could do — walking to locations, mining with the character's reach, placing entities from inventory, crafting recipes, and so on. The goal is to have Claude play the game, not cheat at it.

That said, it may not be perfect. Some actions might inadvertently bypass normal game constraints in ways that aren't immediately obvious. And run_lua in particular executes arbitrary code with no restrictions — it can do basically anything. Use it with that in mind.

Tips

• Start by scanning: Ask Claude to scan_area with a large radius before doing anything. This gives it the lay of the land.
• Coal first: Claude needs coal to fuel burner drills and furnaces. Make sure it sets up a coal supply before building out iron smelting.
• Watch the token usage: Long autonomous runs burn context fast. Break big tasks into phases and check in periodically.
• It makes mistakes: Expect to correct entity placement, inserter directions, and belt routing. The spatial reasoning isn't perfect.