MSSQL MCP Server

⚠️ EXPERIMENTAL USE ONLY — This MCP Server is provided for educational and experimental purposes. It is NOT intended for production use. Use appropriate security measures and test thoroughly before any deployment.

What is this? 🤔

An MCP (Model Context Protocol) server that lets AI assistants like Claude, Cursor, and other LLM-powered tools query and manage your Microsoft SQL Server database using natural language.

Quick Example

You: "Show me all customers from New York"
AI: *queries your MSSQL database and returns the results in plain English*

Features 📊

• Natural language to SQL — Ask questions in plain English
• CRUD operations — Create, read, update, and delete data
• Schema management — Create tables, indexes; describe and drop tables
• Multi-database support — Connect to multiple databases on the same server
• Read-only mode — Restrict to SELECT-only for safer environments
• Secure by default — WHERE clauses required for reads/updates; SQL injection safeguards

Supported AI Clients

• Claude Desktop
• Cursor (VS Code with AI)
• VS Code Agent extension
• Any MCP-compatible client

Quick Start 🚀

One-Click Install (Cursor / VS Code)

Click Add to Cursor or Install in VS Code above to add the MCP server. Edit the config to add your database credentials (DB_USER, DB_PASSWORD, etc.). No cloning required—runs via npx.

Prerequisites

• Node.js 18 or higher
• SQL Server (local, Azure SQL, or remote)
• An MCP-compatible AI client (Claude Desktop, Cursor, etc.)

Installation

From npm (recommended):

npx -y @eamonboyle/mssql-mcp

Or install globally: npm install -g @eamonboyle/mssql-mcp

From source (for development):

git clone https://github.com/eamonboyle/mssql-mcp.git
cd mssql-mcp
npm install
npm run build

Configuration

Environment Variables

Variable	Required	Description
SERVER_NAME	Yes	SQL Server host (e.g., localhost, my-server.database.windows.net)
DATABASE_NAME	Yes	Default database name
DB_USER	Yes*	SQL Server username (for SQL authentication)
DB_PASSWORD	Yes*	SQL Server password (for SQL authentication)
READONLY	No	"true" for read-only mode, "false" for full access (default: "false")
DATABASES	No	Comma-separated list for multi-database access (e.g., ProdDB,StagingDB)
CONNECTION_TIMEOUT	No	Timeout in seconds (default: 30)
TRUST_SERVER_CERTIFICATE	No	"true" for self-signed certs (e.g., local dev) (default: "false")

* Required for SQL authentication. For Windows/Integrated authentication, consult the mssql package documentation.

Option 1: Cursor / VS Code Setup

1. Create or edit .vscode/mcp.json in your workspace:

{
  "mcpServers": {
    "mssql": {
      "command": "npx",
      "args": ["-y", "@eamonboyle/mssql-mcp"],
      "env": {
        "SERVER_NAME": "localhost",
        "DATABASE_NAME": "YourDatabase",
        "DB_USER": "your_username",
        "DB_PASSWORD": "your_password",
        "READONLY": "false"
      }
    }
  }
}

2. Restart Cursor/VS Code.

Option 2: Claude Desktop Setup

1. Open File → Settings → Developer → Edit Config
2. Add the MCP server configuration:

{
  "mcpServers": {
    "mssql": {
      "command": "npx",
      "args": ["-y", "@eamonboyle/mssql-mcp"],
      "env": {
        "SERVER_NAME": "localhost",
        "DATABASE_NAME": "YourDatabase",
        "DB_USER": "your_username",
        "DB_PASSWORD": "your_password",
        "READONLY": "false"
      }
    }
  }
}

3. Restart Claude Desktop.

Multi-Database Support

To allow queries across multiple databases:

"env": {
  "SERVER_NAME": "your-server.database.windows.net",
  "DATABASE_NAME": "ProdDB",
  "DATABASES": "ProdDB,StagingDB,AnalyticsDB",
  "DB_USER": "your_username",
  "DB_PASSWORD": "your_password",
  "READONLY": "false"
}

All tools accept an optional databaseName parameter. When omitted, DATABASE_NAME is used.

Sample Configurations

See src/samples/ for example configs:

• claude_desktop_config.json — Claude Desktop
• vscode_agent_config.json — VS Code Agent

Usage Examples

Once configured, you can ask things like:

• "Show me all users from New York"
• "Create a new table called products with columns for id, name, and price"
• "Update all pending orders to completed status"
• "List all tables in the database"
• "Describe the schema of the customers table"

Available Tools

Tool	Read-only	Description
read_data	✓	Execute SELECT queries
list_table	✓	List tables in a database
describe_table	✓	Get table schema
insert_data		Insert rows
update_data		Update rows (requires WHERE)
create_table		Create tables
create_index		Create indexes
drop_table		Drop tables

Security Notes

• Credentials — Never commit DB_USER/DB_PASSWORD or config files with secrets. Use environment variables or a secrets manager.
• Read-only mode — Set READONLY: "true" when you only need queries.
• WHERE clauses — Read and update operations require explicit WHERE clauses to reduce accidental full-table operations.
• SQL injection — The server validates and restricts dangerous SQL patterns.

Contributing

Contributions are welcome! Please read CONTRIBUTING.md for guidelines. By participating, you agree to uphold our Code of Conduct.

License

MIT License — see LICENSE for details.