Microsoft SQL Server MCP Server

A Model Context Protocol (MCP) server for secure SQL Server database access through Claude Desktop, built with FastMCP 2.9.2 for modern async performance and enhanced developer experience.

✨ Key Features

• 🔍 Database Discovery: List tables, schemas, and databases
• 📊 SQL Execution: Execute queries with proper validation and security
• 🔐 Multi-Auth Support: SQL, Windows, and Azure AD authentication
• 🏢 Platform Support: LocalDB, SQL Server Express, and Azure SQL
• ⚡ Async Performance: Built on FastMCP 2.9.2 with async/await patterns
• 🛡️ Security First: SQL injection prevention and query validation
• 📝 Rich Resources: Discoverable table schemas and data resources
• 🔌 Flexible Configuration: Environment-based configuration with validation

🚀 Tools & Resources

Tools

• execute_sql - Execute SQL queries with validation and logging
• get_table_schema - Retrieve detailed table schema information
• list_databases - Enumerate available databases on the server

Resources

• mssql://tables - List all available tables
• mssql://table/{table_name} - Get specific table data and schema

Quick Start

Install with Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "mssql": {
      "command": "uvx",
      "args": ["microsoft_sql_server_mcp"],
      "env": {
        "MSSQL_SERVER": "localhost",
        "MSSQL_DATABASE": "your_database",
        "MSSQL_USER": "your_username",
        "MSSQL_PASSWORD": "your_password"
      }
    }
  }
}

Configuration

Basic SQL Authentication

MSSQL_SERVER=localhost          # Required
MSSQL_DATABASE=your_database    # Required
MSSQL_USER=your_username        # Required for SQL auth
MSSQL_PASSWORD=your_password    # Required for SQL auth

Windows Authentication

MSSQL_SERVER=localhost
MSSQL_DATABASE=your_database
MSSQL_WINDOWS_AUTH=true         # Use Windows credentials

Azure SQL Database

MSSQL_SERVER=your-server.database.windows.net
MSSQL_DATABASE=your_database
MSSQL_USER=your_username
MSSQL_PASSWORD=your_password
# Encryption is automatic for Azure

Optional Settings

MSSQL_PORT=1433                 # Custom port (default: 1433)
MSSQL_ENCRYPT=true              # Force encryption

Alternative Installation Methods

Using pip

pip install microsoft_sql_server_mcp

Then in claude_desktop_config.json:

{
  "mcpServers": {
    "mssql": {
      "command": "python",
      "args": ["-m", "mssql_mcp_server"],
      "env": { ... }
    }
  }
}

🔧 Development & Testing

Running Tests

# Run refactoring validation tests
python test_refactor.py

# Run full test suite
python -m pytest tests/

Example Usage

# Copy example environment file
cp .env.example .env

# Edit configuration
nano .env

# Run example usage script
python example_usage.py

🛡️ Security Best Practices

• Dedicated User: Create a dedicated SQL user with minimal permissions
• No Admin Access: Never use admin/sa accounts in production
• Windows Auth: Use Windows Authentication when possible
• Encryption: Enable encryption for sensitive data connections
• Query Validation: All queries are validated against injection patterns
• Secure Logging: Sensitive data is masked in logs

🏗️ Architecture

This server is built with:

• FastMCP 2.9.2: Modern async MCP framework with context injection
• Pydantic V2: Configuration validation and data modeling
• Thread Pool: Async wrapper for synchronous pymssql operations
• Security Layer: SQL injection prevention and query validation
• Comprehensive Logging: Detailed logging with context awareness

📝 License

MIT