MotherDuck MCP Server

What is MotherDuck MCP Server about?

Provides a Model Context Protocol (MCP) server that connects to local DuckDB files or cloud‑hosted MotherDuck instances, exposing a single query tool so AI assistants, IDE extensions, and other clients can run SQL against any size of data.

How to use MotherDuck MCP Server?

Install uv (or uvx) – the preferred package runner.
Run the server with desired options, for example:
```
uvx mcp-server-motherduck --transport stream --db-path md: --motherduck-token YOUR_TOKEN
```
- Use --db-path to point to a local DuckDB file (/path/to.db), an in‑memory database (:memory:), or md: for MotherDuck.
- Add --read-only for safe concurrent reads, --saas-mode for tighter security, and --json-response when using HTTP streaming.
Configure your AI or IDE client (Cursor, VS Code, Claude Desktop/Code) by adding an MCP server entry that launches the command above.

Key features of MotherDuck MCP Server

Hybrid execution – query local DuckDB and remote MotherDuck within the same session.
Cloud storage integration – seamless access to data stored in S3 or other cloud providers via MotherDuck.
Data sharing – create and share databases across users.
Serverless architecture – no need to manage instances or clusters.
Multiple transports – stdio, sse, and stream modes for local or networked use.
Read‑scaling tokens & SaaS mode – secure read‑only deployments for third‑party tools.

Use cases of MotherDuck MCP Server

AI‑driven data exploration in IDEs (Cursor, VS Code) without leaving the editor.
Automated analytics pipelines that issue SQL from Claude or other assistants.
Collaborative data notebooks where multiple users query the same MotherDuck warehouse.
Secure, read‑only analytics dashboards for external partners.
Rapid prototyping of data models using DuckDB locally, then scaling to MotherDuck.

FAQ from the MotherDuck MCP Server

Q: Do I need a local DuckDB installation? A: No. The server bundles DuckDB; it can create an in‑memory database on the fly.

Q: How do I authenticate to MotherDuck? A: Provide a token via --motherduck-token or set the MOTHERDUCK_TOKEN environment variable.

Q: Can I run the server behind a firewall? A: Yes. Use --transport sse with a custom port and expose only the needed endpoint.

Q: What is the purpose of --read-only? A: It creates short‑lived read‑only connections, allowing many tools to query concurrently without locking.

Q: How do I enable JSON responses? A: Add the --json-response flag when using the stream transport.

MotherDuck's DuckDB MCP Server

An MCP server implementation that interacts with DuckDB and MotherDuck databases, providing SQL analytics capabilities to AI Assistants and IDEs.

Resources

Features

Hybrid execution: query data from local DuckDB or/and cloud-based MotherDuck databases
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 your AI Assistant or IDE
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 DuckDB or MotherDuck database
- Inputs:
  - query (string, required): The SQL query to execute

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

Command Line Parameters

The MCP server supports the following parameters:

Parameter	Type	Default	Description
`--transport`	Choice	`stdio`	Transport type. Options: `stdio`, `sse`, `stream`
`--port`	Integer	`8000`	Port to listen on for sse and stream transport mode
`--db-path`	String	`md:`	Path to local DuckDB database file or MotherDuck database
`--motherduck-token`	String	`None`	Access token to use for MotherDuck database connections (uses `motherduck_token` env var by default)
`--read-only`	Flag	`False`	Flag for connecting to DuckDB or MotherDuck in read-only mode. For DuckDB it uses short-lived connections to enable concurrent access
`--home-dir`	String	`None`	Home directory for DuckDB (uses `HOME` env var by default)
`--saas-mode`	Flag	`False`	Flag for connecting to MotherDuck in SaaS mode. (disables filesystem and write permissions for local DuckDB)
`--json-response`	Flag	`False`	Enable JSON responses for HTTP stream. Only supported for `stream` transport

Quick Usage Examples

# Connect to local DuckDB file in read-only mode with stream transport mode
uvx mcp-server-motherduck --transport stream --db-path /path/to/local.db --read-only

# Connect to MotherDuck with token with stream transport mode
uvx mcp-server-motherduck --transport stream --db-path md: --motherduck-token YOUR_TOKEN

# Connect to local DuckDB file in read-only mode with stream transport mode
uvx mcp-server-motherduck --transport stream --db-path /path/to/local.db --read-only

# Connect to MotherDuck in SaaS mode for enhanced security with stream transport mode
uvx mcp-server-motherduck --transport stream --db-path md: --motherduck-token YOUR_TOKEN --saas-mode

Getting Started

General Prerequisites

uv installed, you can install it using pip install uv or brew install uv

If you plan to use the MCP with Claude Desktop or any other MCP comptabile client, the client need to be installed.

Prerequisites for DuckDB

No prerequisites. The MCP server can create an in-memory database on-the-fly
Or connect to an existing local DuckDB database file , or one stored on remote object storage (e.g., AWS S3).

See Connect to local DuckDB.

Prerequisites for MotherDuck

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

Usage with Cursor

Install Cursor from cursor.com/downloads if you haven't already
Open Cursor:

To set it up globally for the first time, go to Settings->MCP and click on "+ Add new global MCP server".
This will open a mcp.json file to which you add the following configuration:

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

Usage with VS Code

For the quickest installation, click one of the "Install with UV" buttons at the top.

Manual Installation

Add the following JSON block to your User Settings (JSON) file in VS Code. You can do this by pressing Ctrl + Shift + P and typing Preferences: Open User Settings (JSON).

{
  "mcp": {
    "inputs": [
      {
        "type": "promptString",
        "id": "motherduck_token",
        "description": "MotherDuck Token",
        "password": true
      }
    ],
    "servers": {
      "motherduck": {
        "command": "uvx",
        "args": [
          "mcp-server-motherduck",
          "--db-path",
          "md:",
          "--motherduck-token",
          "${input:motherduck_token}"
        ]
      }
    }
  }
}

Optionally, you can add it to a file called .vscode/mcp.json in your workspace. This will allow you to share the configuration with others.

{
  "inputs": [
    {
      "type": "promptString",
      "id": "motherduck_token",
      "description": "MotherDuck Token",
      "password": true
    }
  ],
  "servers": {
    "motherduck": {
      "command": "uvx",
      "args": [
        "mcp-server-motherduck",
        "--db-path",
        "md:",
        "--motherduck-token",
        "${input:motherduck_token}"
      ]
    }
  }
}

Usage with Claude Desktop

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

Usage with Claude Code

Claude Code supports MCP servers through CLI commands or JSON configuration. Here are two ways to set it up:

Option 1: Using CLI Commands

Add the MotherDuck MCP server directly using the Claude Code CLI:

claude mcp add mcp-server-motherduck uvx mcp-server-motherduck -- --db-path md: --motherduck-token <YOUR_MOTHERDUCK_TOKEN_HERE>

Option 2: Using JSON Configuration

Add the server using a JSON configuration:

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

Scoping Options:

Use --local (default) for project-specific configuration
Use --project to share the configuration with your team via .mcp.json
Use --user to make the server available across all your projects

Important Notes:

Replace YOUR_MOTHERDUCK_TOKEN_HERE with your actual MotherDuck token
Claude Code also supports environment variable expansion, so you can use ${MOTHERDUCK_TOKEN} if you've set the environment variable

Securing your MCP Server when querying MotherDuck

If the MCP server is exposed to third parties and should only have read access to data, we recommend using a read scaling token and running the MCP server in SaaS mode.

Read Scaling Tokens are special access tokens that enable scalable read operations by allowing up to 4 concurrent read replicas, improving performance for multiple end users while restricting write capabilities. Refer to the Read Scaling documentation to learn how to create a read-scaling token.

SaaS Mode in MotherDuck enhances security by restricting it's access to local files, databases, extensions, and configurations, making it ideal for third-party tools that require stricter environment protection. Learn more about it in the SaaS Mode documentation.

Secure Configuration

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

Connect to local DuckDB

To connect to a local DuckDB, instead of using the MotherDuck token, specify the path to your local DuckDB database file or use :memory: for an in-memory database.

In-memory database:

{
  "mcpServers": {
    "mcp-server-motherduck": {
      "command": "uvx",
      "args": [
        "mcp-server-motherduck",
        "--db-path",
        ":memory:"
      ]
    }
  }
}

Local DuckDB file:

{
  "mcpServers": {
    "mcp-server-motherduck": {
      "command": "uvx",
      "args": [
        "mcp-server-motherduck",
        "--db-path",
        "/path/to/your/local.db"
      ]
    }
  }
}

Local DuckDB file in readonly mode:

{
  "mcpServers": {
    "mcp-server-motherduck": {
      "command": "uvx",
      "args": [
        "mcp-server-motherduck",
        "--db-path",
        "/path/to/your/local.db",
        "--read-only"
      ]
    }
  }
}

Note: readonly mode for local file-backed DuckDB connections also makes use of short lived connections. Each time the query MCP tool is used a temporary, reaodnly connection is created + query is executed + connection is closed. This feature was motivated by a workflow where DBT was for modeling data within duckdb and then an MCP client (Windsurf/Cline/Claude/Cursor) was used for exploring the database. The short lived connections allow each tool to run and then release their connection, allowing the next tool to connect.

Example Queries

Once configured, you can e.g. 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"

Running in SSE mode

The server can run in SSE mode in two ways:

Direct SSE mode

Run the server directly in SSE mode using the --transport sse flag:

uvx mcp-server-motherduck --transport sse --port 8000 --db-path md: --motherduck-token <your_motherduck_token>

This will start the server listening on the specified port (default 8000) and you can point your clients directly to this endpoint.

Using supergateway

Alternatively, you can run SSE mode using supergateway:

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

Both methods allow you to point your clients such as Claude Desktop, Cursor to the SSE endpoint.

Development configuration

To run the server from a local development environment, use the following configuration:

 {
  "mcpServers": {
    "mcp-server-motherduck": {
      "command": "uv",
      "args": [
        "--directory",
        "/path/to/your/local/mcp-server-motherduck",
        "run",
        "mcp-server-motherduck",
        "--db-path",
        "md:",
        "--motherduck-token",
        "<YOUR_MOTHERDUCK_TOKEN_HERE>"
      ]
    }
  }
}

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.

mcp-name: io.github.motherduckdb/mcp-server-motherduck