# MSSQL MCP Server

A Model Context Protocol (MCP) server for read-only Microsoft SQL Server interactions. This server provides safe, read-only access to MSSQL databases through the MCP protocol.

## Features

- **Read-only operations**: Only SELECT, DECLARE, and SET (for local variables) queries are allowed
- **Schema exploration**: Browse databases, tables, columns, and indexes
- **Safe querying**: SQL injection protection and query validation
- **Connection management**: Secure connection handling with proper cleanup

## Installation

1. Clone this repository:
```bash
git clone <repository-url>
cd mssql-mcp
```

2. Install dependencies:
```bash
pip install -e .
```

3. Set up environment variables:
```bash
cp .env.example .env
# Edit .env with your database connection details
```

**Important:** The server automatically loads environment variables from a `.env` file in the current directory. Make sure to create this file with your database connection details.

## Configuration

Create a `.env` file with your MSSQL connection details:

```env
MSSQL_SERVER=localhost
MSSQL_DATABASE=your_database
MSSQL_USERNAME=your_username
MSSQL_PASSWORD=your_password
MSSQL_PORT=1433
MSSQL_TIMEOUT=30
MSSQL_CHARSET=UTF-8
MSSQL_AUTOCOMMIT=true
```

## Usage

### Development Mode
```bash
mcp dev src/mssql_mcp/server.py
```

### Claude Desktop Integration
```bash
mcp install src/mssql_mcp/server.py --name "MSSQL Server"
```

### Direct Execution
```bash
python -m mssql_mcp.server
```

## Available Resources

- `db://schemas` - List all schemas in the current database
- `db://tables/{database}` - List all tables in the current database
- `db://schema_tables/{schema_name}` - List tables in a specific schema
- `db://columns/{schema_name}/{table_name}` - Get column information for a table
- `db://indexes/{database}/{schema_name}/{table_name}` - Get index information for a table

## Available Tools

- `list_databases` - List all accessible databases
- `list_tables` - List tables in the current database

## Security

This server implements several security measures:

- Only SELECT, DECLARE, and SET (for local variables) statements are allowed
- SQL parsing and validation
- Parameterized queries where possible
- Connection string security
- No DDL or DML operations permitted

## Requirements

- Python 3.9+
- Access to a Microsoft SQL Server instance
- pymssql library (automatically installed with dependencies)

## License

MIT License