# MCP SQL Server
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A Model Context Protocol (MCP) server for SQL Server integration with Claude Code. Query, monitor, and analyze your SQL Server databases directly from Claude.
## Features
- **Query Execution** - Execute SELECT queries with parameterized inputs
- **Schema Exploration** - Browse tables, columns, procedures, and indexes
- **Database Monitoring** - Track active queries, blocking sessions, wait stats, and connections
- **Performance Analysis** - Identify missing indexes, unused indexes, and fragmentation
- **Write Operations** - INSERT, UPDATE, DELETE when enabled (READONLY=false)
## Installation
### Option 1: From npm (recommended)
```bash
npx @fabriciofs/mcp-sql-server
```
### Option 2: Global installation
```bash
npm install -g @fabriciofs/mcp-sql-server
```
### Option 3: Clone and build locally
```bash
git clone https://github.com/fabriciofs/mcp-sql-server.git
cd mcp-sql-server
npm install
npm run build
```
## Configuration
### Claude Code Integration
Add to your Claude Code MCP settings (`~/.claude/settings.json` or project `.claude/settings.json`):
```json
{
"mcpServers": {
"sqlserver": {
"command": "npx",
"args": ["-y", "@fabriciofs/mcp-sql-server"],
"env": {
"SQL_CONNECTION_URL": "sqlserver://user:password@localhost:1433/database",
"READONLY": "true"
}
}
}
}
```
Or with individual connection parameters:
```json
{
"mcpServers": {
"sqlserver": {
"command": "npx",
"args": ["-y", "@fabriciofs/mcp-sql-server"],
"env": {
"SQL_SERVER": "localhost",
"SQL_DATABASE": "mydb",
"SQL_USER": "sa",
"SQL_PASSWORD": "yourpassword",
"SQL_PORT": "1433",
"SQL_TRUST_CERT": "true",
"READONLY": "true"
}
}
}
}
```
### Environment Variables
#### Connection (choose one method)
**Method 1: Connection URL**
```bash
SQL_CONNECTION_URL=sqlserver://user:password@host:port/database?TrustServerCertificate=true
```
**Method 2: Individual Parameters**
```bash
SQL_SERVER=localhost
SQL_DATABASE=mydb
SQL_USER=sa
SQL_PASSWORD=yourpassword
SQL_PORT=1433 # Optional, default: 1433
SQL_ENCRYPT=true # Optional, default: true
SQL_TRUST_CERT=false # Optional, default: false
```
#### Required Settings
| Variable | Description |
|----------|-------------|
| `READONLY` | **Required.** Set to `true` for read-only mode or `false` to enable write operations |
#### Optional Settings
| Variable | Default | Description |
|----------|---------|-------------|
| `QUERY_TIMEOUT` | `30000` | Query timeout in milliseconds (max: 120000) |
| `MAX_ROWS` | `1000` | Maximum rows to return (max: 5000) |
| `POOL_MIN` | `2` | Minimum connection pool size |
| `POOL_MAX` | `10` | Maximum connection pool size |
| `LOG_LEVEL` | `info` | Log level: debug, info, warn, error |
## Available Tools
### Query Tools
| Tool | Description |
|------|-------------|
| `sql_execute` | Execute SELECT queries with parameterized inputs |
### Schema Tools
| Tool | Description |
|------|-------------|
| `schema_list_tables` | List all tables and views in the database |
| `schema_describe_table` | Get detailed table information (columns, indexes, foreign keys) |
| `schema_list_columns` | Search for columns across all tables |
| `schema_list_procedures` | List stored procedures |
| `schema_list_indexes` | List indexes with usage statistics |
### Monitor Tools
| Tool | Description |
|------|-------------|
| `monitor_active_queries` | Monitor currently running queries |
| `monitor_blocking` | Monitor blocking sessions and lock chains |
| `monitor_wait_stats` | Monitor wait statistics for performance bottlenecks |
| `monitor_database_size` | Monitor database size and file usage |
| `monitor_connections` | Monitor active connections |
| `monitor_performance_counters` | Monitor SQL Server performance counters |
### Analysis Tools
| Tool | Description |
|------|-------------|
| `analyze_query` | Analyze query execution plan and statistics |
| `analyze_suggest_indexes` | Suggest missing indexes based on query patterns |
| `analyze_unused_indexes` | Find indexes that are not being used |
| `analyze_duplicate_indexes` | Find duplicate or overlapping indexes |
| `analyze_fragmentation` | Analyze index fragmentation levels |
| `analyze_statistics` | Analyze table statistics for stale data |
### Write Tools (READONLY=false only)
| Tool | Description |
|------|-------------|
| `sql_insert` | Insert a row into a table |
| `sql_update` | Update rows in a table |
| `sql_delete` | Delete rows from a table |
## Usage Examples
Once configured, you can ask Claude to interact with your database:
```
"List all tables in the database"
"Describe the Users table"
"Show me active queries running for more than 5 seconds"
"Find unused indexes in the Orders table"
"Analyze the fragmentation of all indexes"
"What are the top wait statistics?"
```
## Security Considerations
- **Always use READONLY=true in production** unless write access is explicitly required
- Store credentials securely using environment variables
- Use SQL Server accounts with minimal required permissions
- Consider network security (VPN, firewall rules) for remote connections
## Requirements
- Node.js >= 20.0.0
- SQL Server 2016 or later
- Appropriate SQL Server permissions for the operations you want to perform
## Development
```bash
# Install dependencies
npm install
# Build
npm run build
# Development mode (watch)
npm run dev
# Type check
npm run typecheck
# Run MCP Inspector
npm run inspector
```
## License
MIT License - see [LICENSE](LICENSE) file for details.
