# SQL Server MCP

A read-only MCP (Model Context Protocol) server for SQL Server database introspection. Use with Claude Desktop to let Claude explore and query your SQL Server databases.

## Features

- List databases, tables, views, stored procedures, and functions
- Get object definitions (DDL/source code)
- Execute read-only SELECT queries
- Search for objects across databases
- **Read-only by design** - all mutation queries are blocked

## Installation

```bash
# Clone the repo
git clone https://github.com/millelog/sql-server-mcp.git
cd sql-server-mcp

# Install in a virtual environment
python -m venv .venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate
pip install -e .
```

## Claude Desktop Configuration

Add to your Claude Desktop config file:

- **Windows:** `%APPDATA%\Claude\claude_desktop_config.json`
- **macOS:** `~/Library/Application Support/Claude/claude_desktop_config.json`

```json
{
  "mcpServers": {
    "sql-server": {
      "command": "python",
      "args": ["-m", "sql_server_mcp"],
      "cwd": "C:\\path\\to\\sql-server-mcp",
      "env": {
        "MSSQL_HOST": "your-server",
        "MSSQL_USER": "your-username",
        "MSSQL_PASSWORD": "your-password",
        "MSSQL_DATABASE": "master"
      }
    }
  }
}
```

Restart Claude Desktop after updating the config.

## Configuration Options

| Variable                  | Description                              | Default     |
| ------------------------- | ---------------------------------------- | ----------- |
| `MSSQL_HOST`              | SQL Server hostname                      | `localhost` |
| `MSSQL_PORT`              | SQL Server port                          | `1433`      |
| `MSSQL_USER`              | Username                                 | -           |
| `MSSQL_PASSWORD`          | Password                                 | -           |
| `MSSQL_DATABASE`          | Default database                         | `master`    |
| `MSSQL_CONNECTION_STRING` | Full connection string (overrides above) | -           |
| `MAX_ROWS`                | Maximum rows returned                    | `100`       |
| `QUERY_TIMEOUT`           | Query timeout (seconds)                  | `30`        |
| `ALLOWED_DATABASES`       | Comma-separated allowlist                | -           |
| `BLOCKED_DATABASES`       | Comma-separated blocklist                | -           |

## Available Tools

| Tool                       | Description                                       |
| -------------------------- | ------------------------------------------------- |
| `list_databases`           | List all accessible databases                     |
| `list_tables`              | List tables in a database                         |
| `get_table_definition`     | Get CREATE TABLE DDL                              |
| `get_table_columns`        | Get column metadata                               |
| `get_table_indexes`        | Get index information                             |
| `get_table_relationships`  | Get foreign key relationships                     |
| `list_views`               | List views in a database                          |
| `get_view_definition`      | Get CREATE VIEW DDL                               |
| `list_procedures`          | List stored procedures                            |
| `get_procedure_definition` | Get CREATE PROCEDURE DDL                          |
| `get_procedure_parameters` | Get procedure parameters                          |
| `list_functions`           | List user-defined functions                       |
| `get_function_definition`  | Get CREATE FUNCTION DDL                           |
| `execute_query`            | Run read-only SELECT queries                      |
| `get_sample_data`          | Get sample rows from a table                      |
| `search_objects`           | Search for objects by name                        |
| `search_definitions`       | Search within object definitions                  |
| `get_schema_overview`      | Get database schema summary (object counts, size) |

## Development

```bash
# Run tests
pytest tests/ -v

# Run with coverage
pytest tests/ --cov=src/sql_server_mcp
```

## License

MIT