Chess UCI MCP server

chess-uci-mcp

An MCP bridge that provides an interface to UCI chess engines (such as Stockfish or Leela Chess Zero).

<!-- mcp-name: io.github.AnglerfishChess/chess-uci-mcp -->

The UCI side runs on esca: it speaks the protocol to the engine and answers every chess question the bridge has along the way.

Dependencies

You need to have Python 3.12 or newer, and also uv/uvx installed.

Usage

To function, it requires an installed UCI-compatible chess engine, like Stockfish (has been tested with Stockfish 17).

In case of Stockfish, you can download it from https://stockfishchess.org/download/.

On macOS, you can use brew install stockfish.

You need to find out the path to your UCI-capable engine binary; for further example configuration, the path is e.g. /usr/local/bin/stockfish (which is default for Stockfish installed on macOS using Brew).

The further configuration should be done in your MCP setup; for Claude Desktop, this is the file claudedesktopconfig.json (find it in Settings menu, Developer, then Edit Config).

The full path on different OSes

• macOS: ~/Library/Application\ Support/Claude/claudedesktopconfig.json
• Windows: %APPDATA%/Claude/claudedesktopconfig.json
• Linux: ~/.config/Claude/claudedesktopconfig.json

Add the following settings to your MCP configuration (depending on the way to run it you prefer):

Uvx (recommended)

Uvx is able to directly run the Python application by its name, ensuring all the dependencies, in a automatically-created virtual environment. This is the preferred way to run the chess-uci-mcp bridge.

Set up your MCP server configuration (e.g. Claude Desktop configuration) file as following:

"mcpServers": {
  "chess-uci-mcp": {
    "command": "uvx",
    "args": ["chess-uci-mcp@latest", "/usr/local/bin/stockfish"]
  }
}

To pass options to the engine, add them to the args array. For example, to set the Threads and Hash options for Stockfish:

"mcpServers": {
  "chess-uci-mcp": {
    "command": "uvx",
    "args": [
      "chess-uci-mcp@latest", 
      "/usr/local/bin/stockfish",
      "-o", "Threads", "4",
      "-o", "Hash", "128"
    ]
  }
}

Uv

Use it if you have the repository cloned locally and run from it:

"mcpServers": {
  "chess-uci-mcp": {
    "command": "uv",
    "args": ["run", "chess-uci-mcp", "/usr/local/bin/stockfish"]
  }
}

Similarly, to pass options when running with uv:

"mcpServers": {
  "chess-uci-mcp": {
    "command": "uv",
    "args": [
      "run", 
      "chess-uci-mcp", 
      "/usr/local/bin/stockfish",
      "-o", "Threads", "4",
      "-o", "Hash", "128"
    ]
  }
}

Command-line Options

The application accepts the following command-line options:

• ENGINE_PATH: (Required) The path to the UCI-compatible chess engine executable.
• --uci-option or -o: Set a UCI option. This option can be used multiple times. It takes two arguments: the option name and its value (e.g., -o Threads 4).
• --think-time: The default thinking time for the engine in milliseconds. Defaults to 1000.
• --debug: Enable debug logging.

Available MCP Commands

The bridge provides the following MCP commands:

1. analyze - Analyze a chess position specified by FEN string
2. getbestmove - Get the best move for a chess position
3. set_position - Set the current chess position
4. engine_info - Get information about the chess engine
5. getengineoptions - Get all available UCI engine options with their metadata and current values
6. setengineoptions - Set one or more UCI engine options at runtime

Development

# Clone the repository
git clone https://github.com/AnglerfishChess/chess-uci-mcp.git
# ... or
#    git clone git@github.com:AnglerfishChess/chess-uci-mcp.git

cd chess-uci-mcp

# Create a virtual environment
uv venv --python python3.13

Shortened. The full README is on GitHub.