MCP SQL Server

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)

npx @fabriciofs/mcp-sql-server

Option 2: Global installation

npm install -g @fabriciofs/mcp-sql-server

Option 3: Clone and build locally

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):

{
  "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:

{
  "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

SQL_CONNECTION_URL=sqlserver://user:password@host:port/database?TrustServerCertificate=true

Method 2: Individual Parameters

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

# 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 file for details.