SQL MCP Server

A Model Context Protocol (MCP) server that exposes a SQLite database to any MCP-compatible client — including Claude Desktop, Claude Code, and custom agents.

What it does

Gives an AI assistant structured, read-safe access to a relational database through five tools. The assistant can explore the schema, run SELECT queries, and retrieve sample data — without any risk of writes or destructive operations.

Schema

Five tables with realistic foreign-key relationships:

users ──< orders ──< order_items >── products
  │
  └──< support_tickets

MCP Tools

Security

• run_query checks the first SQL token and rejects anything that isn't SELECT

• Multi-statement queries (containing ;) are blocked

• Table name parameters are validated against [A-Za-z_][A-Za-z0-9_]* before interpolation

Setup

1. Install dependencies

pip install -r requirements.txt

2. Seed the database

python seed.py

This creates test.db in the same directory with all 5 tables populated.

3. Run the server

python server.py

The server communicates over stdio using the MCP protocol.

Claude Desktop Integration

Add the following to your claude_desktop_config.json:

{
  "mcpServers": {
    "sql-mcp": {
      "command": "python3",
      "args": ["/absolute/path/to/server.py"]
    }
  }
}

Config file locations:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

Restart Claude Desktop after saving.

Verify Tools (without Claude Desktop)

test_tools.py connects to the server via stdio and exercises all 5 tools:

python test_tools.py

Expected output confirms:

• All 5 tools are registered

• Each tool returns correct results

• run_query rejects non-SELECT statements

Project Structure

.
├── server.py         # MCP server — 5 tools
├── seed.py           # Creates and populates test.db
├── test_tools.py     # Stdio client verification script
├── requirements.txt  # mcp, aiosqlite
└── .gitignore

Requirements

• Python 3.10+

• mcp — MCP server framework

• aiosqlite — async SQLite driver