Configuration

Required Parameters

• db-path (string): Path to the DuckDB database file
  • The server will automatically create the database file and parent directories if they don't exist
  • If --readonly is specified and the database file doesn't exist, the server will fail to start with an error

Optional Parameters

• --readonly: Run server in read-only mode (default: false)
  • Description: When this flag is set, the server operates in read-only mode. This means:
    • The DuckDB database will be opened with read_only=True, preventing any write operations.
    • If the specified database file does not exist, it will not be created.
    • Security Benefit: Prevents the Language Model (LLM) from performing any write operations, ensuring that the database remains unaltered.
  • Reference: For more details on read-only connections in DuckDB, see the DuckDB Python API documentation.
• --keep-connection: Re-uses a single DuckDB connection mode (default: false)
  • Description: When this flag is set, Re-uses a single DuckDB connection for the entire server lifetime. Enables TEMP objects & slightly faster queries, but can hold an exclusive lock on the file.

Installation

Installing via Smithery

To install DuckDB Server for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install mcp-server-duckdb --client claude

Claude Desktop Integration

Configure the MCP server in Claude Desktop's configuration file:

MacOS

Location: ~/Library/Application Support/Claude/claude_desktop_config.json

Windows

Location: %APPDATA%/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "duckdb": {
      "command": "uvx",
      "args": [
        "mcp-server-duckdb",
        "--db-path",
        "~/mcp-server-duckdb/data/data.db"
      ]
    }
  }
}

• Note: ~/mcp-server-duckdb/data/data.db should be replaced with the actual path to the DuckDB database file.

Development

Prerequisites

• Python with uv package manager
• DuckDB Python package
• MCP server dependencies

Debugging

Debugging MCP servers can be challenging due to their stdio-based communication. We recommend using the MCP Inspector for the best debugging experience.

Using MCP Inspector

1. Install the inspector using npm:

npx @modelcontextprotocol/inspector uv --directory ~/codes/mcp-server-duckdb run mcp-server-duckdb --db-path ~/mcp-server-duckdb/data/data.db

2. Open the provided URL in your browser to access the debugging interface

The inspector provides visibility into:

• Request/response communication
• Tool execution
• Server state
• Error messages