MotherDuck MCP Server

An MCP server implementation that integrates MotherDuck and local DuckDB, providing SQL analytics capabilities to Claude.

Features

• Hybrid execution: query data from both cloud-based MotherDuck and local DuckDB
• Cloud storage integration: access data stored in Amazon S3 or other cloud storage thanks to MotherDuck's integrations
• Data sharing: create and share databases
• SQL analytics: use DuckDB's SQL dialect to query any size of data directly from Claude
• Serverless architecture: run analytics without needing to configure instances or clusters

Components

Prompts

The server provides one prompt:

• duckdb-motherduck-initial-prompt: A prompt to initialize a connection to DuckDB or MotherDuck and start working with it

Tools

The server offers one tool:

• query: Execute a SQL query on the MotherDuck/DuckDB database
  • Inputs:
    • query (string, required): The SQL query to execute

All interactions with both DuckDB and MotherDuck are done through writing SQL queries.

Getting Started

Prerequisites

• A MotherDuck account (sign up at motherduck.com)
• A MotherDuck access token
• uv installed, you can install it using pip install uv or brew install uv

If you plan to use MotherDuck MCP with Claude Desktop, you will also need Claude Desktop installed.

Setting up your MotherDuck token

1. Sign up for a MotherDuck account
2. Generate an access token via the MotherDuck UI
3. Store the token securely for use in the configuration

Usage with Claude Desktop

1. Install Claude Desktop from claude.ai/download if you haven't already

2. Open the Claude Desktop configuration file:

• To quickly access it or create it the first time, open the Claude Desktop app, select Settings, and click on the "Developer" tab, finally click on the "Edit Config" button.
• Add the following configuration to your claude_desktop_config.json:

"mcpServers": {
  "mcp-server-motherduck": {
    "command": "uvx",
    "args": [
      "mcp-server-motherduck",
      "--db-path",
      "md:",
      "--motherduck-token",
      "<YOUR_MOTHERDUCK_TOKEN_HERE>",
    ],
  }
}

Important Notes:

• Replace YOUR_MOTHERDUCK_TOKEN_HERE with your actual MotherDuck token
• Replace YOUR_HOME_FOLDER_PATH with the path to your home directory (needed by DuckDB for file operations). For example, on macOS, it would be /Users/your_username
• The HOME environment variable is required for DuckDB to function properly.

Example Queries

Once configured, you can ask Claude to run queries like:

• "Create a new database and table in MotherDuck"
• "Query data from my local CSV file"
• "Join data from my local DuckDB database with a table in MotherDuck"
• "Analyze data stored in Amazon S3"

Testing

The server is designed to be run by tools like Claude Desktop and Cursor, but you can start it manually for testing purposes. When testing the server manually, you can specify which database to connect to using the --db-path parameter:

1. Default MotherDuck database:

   • To connect to the default MotherDuck database, you will need to pass the auth token using the --motherduck-token parameter.

   uvx mcp-server-motherduck --db-path md: --motherduck-token <your_motherduck_token>
   

2. Specific MotherDuck database:

   uvx mcp-server-motherduck --db-path md:your_database_name --motherduck-token <your_motherduck_token>
   

3. Local DuckDB database:

   uvx mcp-server-motherduck --db-path /path/to/your/local.db
   

4. In-memory database:

   uvx mcp-server-motherduck --db-path :memory:
   

If you don't specify a database path but have set the motherduck_token environment variable, the server will automatically connect to the default MotherDuck database (md:).

Running in SSE mode

The server could also be run ing SSE mode using supergateway by running the following command:

npx -y supergateway --stdio "uvx mcp-server-motherduck --db-path md: --motherduck-token <your_motherduck_token>"

And you can point your clients such as Claude Desktop, Cursor to this endpoint.

Troubleshooting

• If you encounter connection issues, verify your MotherDuck token is correct
• For local file access problems, ensure the --home-dir parameter is set correctly
• Check that the uvx command is available in your PATH
• If you encounter spawn uvx ENOENT errors, try specifying the full path to uvx (output of which uvx)
• In version previous for v0.4.0 we used environment variables, now we use parameters

License

This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.