ktanaka101/mcp-server-duckdb

A Model Context Protocol (MCP) server implementation for DuckDB, providing database interaction capabilities through MCP tools.
It would be interesting to have LLM analyze it. DuckDB is suitable for local analysis.
Overview
This server enables interaction with a DuckDB database through the Model Context Protocol, allowing for database operations like querying, table creation, and schema inspection.
Components
Resources
Currently, no custom resources are implemented.
Prompts
Currently, no custom prompts are implemented.
Tools
The server implements the following database interaction tool:
- **query**: Execute any SQL query on the DuckDB database
- **Input**: query (string) - Any valid DuckDB SQL statement
- **Output**: Query results as text (or success message for operations like CREATE/INSERT)
> [!NOTE]
> The server provides a single unified query function rather than separate specialized functions, as modern LLMs can generate appropriate SQL for any database operation (SELECT, CREATE TABLE, JOIN, etc.) without requiring separate endpoints.
> [!NOTE]
> When the server is running in readonly mode, DuckDB's native readonly protection is enforced.
> This ensures that the Language Model (LLM) cannot perform any write operations (CREATE, INSERT, UPDATE, DELETE), maintaining data integrity and preventing unintended changes.
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: