MSSQL MCP Server

A production-ready Model Context Protocol (MCP) server for Microsoft SQL Server with comprehensive stored procedure management, virtual filesystem protocol, and safe write operations.

Features

• Virtual Filesystem: Browse database objects (stored procedures, views, functions) as files

• Discovery Tools: Search stored procedures, inspect table schemas, analyze dependencies

• Safe Write Operations: SQL validation, transaction management, audit logging

• SP Management: Draft → Test → Deploy → Rollback workflow with version control

• Performance Analysis: Query execution statistics from plan cache

• Security: SQL injection prevention, blocked keywords, row limits

Installation

npm install
npm run build

Configuration

Copy .env.example to .env and configure:

cp .env.example .env

Key configuration options:

• DB_SERVER: SQL Server hostname

• DB_DATABASE: Database name

• DB_USER/DB_PASSWORD: Credentials

• DB_ENCRYPT: Enable encryption (default: true)

• DB_TRUST_SERVER_CERTIFICATE: Trust server certificate for dev environments (default: false)

• ENABLE_WRITE_OPERATIONS: Enable INSERT/UPDATE/DELETE (default: true)

• ENABLE_SP_MODIFICATIONS: Enable stored procedure management (default: true)

• REQUIRE_TRANSACTIONS: Require explicit transactions for modifications (default: true)

• MAX_ROWS_AFFECTED: Maximum rows that can be modified in one operation (default: 10000)

• DRAFT_SCHEMA: Schema for testing SPs before deployment (default: dbo_draft)

• AUTO_BACKUP_BEFORE_DEPLOY: Auto-backup SPs before deploying (default: true)

See .env.example for all options.

Usage with Claude Code

Add to your MCP configuration file (.claude.json or ~/.claude.json):

{
  "mcpServers": {
    "mssql": {
      "command": "node",
      "args": ["/absolute/path/to/sql-server-mcp/dist/index.js"],
      "env": {
        "DB_SERVER": "localhost",
        "DB_DATABASE": "MyDatabase",
        "DB_USER": "sa",
        "DB_PASSWORD": "YourPassword",
        "ENABLE_WRITE_OPERATIONS": "true",
        "ENABLE_SP_MODIFICATIONS": "true"
      }
    }
  }
}

Available Tools

Discovery & Schema

• list_stored_procedures: List stored procedures with pagination

• search_stored_procedures: Search SPs by name or content

• get_table_schema: Get table structure with columns, indexes, foreign keys

• get_dependencies: Analyze object dependencies (callers and references)

• analyze_sp_performance: View execution statistics from plan cache

Execution

• execute_query_write: Execute INSERT/UPDATE/DELETE with validation

Transactions

• begin_transaction: Start a new transaction

• commit_transaction: Commit changes

• rollback_transaction: Undo changes

Stored Procedure Management

• create_sp_draft: Create a draft SP in separate schema

• test_sp_draft: Test draft with parameters

• deploy_sp: Deploy to production (auto-backs up current version)

• rollback_sp: Restore previous version

• list_sp_versions: View version history

Example Workflows

Searching for Stored Procedures

search for stored procedures that modify the Orders table

Viewing Database Objects as Files

show me /database/stored_procedures/dbo/GetCustomerOrders.sql

Modifying a Stored Procedure

I need to update GetCustomerOrders to include email.
Create a draft, test it with CustomerId=123, then deploy.

Safe Data Modifications

Start a transaction, update Customer set Status='Active' where Id=123,
show me the result, then commit.

Performance Analysis

Analyze performance of GetDailySalesReport and show execution stats

Architecture

Phase 1: Read-Only Foundation

• Virtual filesystem for database objects

• Connection pooling (read-only pool)

• Query execution with error handling

• Discovery and schema inspection tools

Phase 2: Safe Writes

• SQL validation and injection prevention

• Transaction manager with timeout protection

• Audit logging for compliance

• Write operation tools

Phase 3: SP Management

• Version control with SPVersionHistory table

• Draft schema for safe testing

• Deploy/rollback workflow

• Automatic backups before deployment

Phase 4: Advanced Features

• Dependency analysis

• Performance monitoring from DMVs

• Reference finding

Security Features

• SQL Validation: Blocks dangerous keywords and patterns

• Parameterized Queries: Prevents SQL injection

• Row Limits: Prevents accidental mass updates

• Transaction Timeouts: Auto-rollback after 5 minutes

• Audit Trail: Logs all operations to file

• Separate Credentials: Optional read-only and read-write connections

Testing

A complete test environment is included in the test/ directory:

cd test
./setup.sh init

This sets up a Docker container with SQL Server 2022 and a test database (MCPTestDB) pre-populated with:

• Sample tables (Customers, Products, Orders, etc.)

• 13 test stored procedures

• Views and functions

• Sample data for testing all MCP features

Connection string for testing:

Server=localhost,1433;Database=MCPTestDB;User Id=sa;Password=McpTest123!;TrustServerCertificate=true

Running Tests

After setting up the test database:

# Run all tests
npm run test:all

# Or run specific tests
npm run test:connection  # Basic connectivity test
npm run test:db         # Database object verification
npm run test:scenarios  # Comprehensive functionality tests

See test/README.md for detailed testing scenarios and management commands.

Development

# Development mode with auto-reload
npm run dev

# Build
npm run build

# Run production build
npm start

# Lint
npm run lint

# Format
npm run format

Project Structure

sql-server-mcp/
├── src/
│   ├── index.ts                    # Entry point
│   ├── server.ts                   # MCP server setup
│   ├── types/                      # TypeScript interfaces
│   ├── config/                     # Configuration and logging
│   ├── database/                   # Connection, query execution, transactions
│   ├── filesystem/                 # Virtual filesystem protocol
│   ├── tools/                      # MCP tool implementations
│   │   ├── discovery/              # Search and discovery
│   │   ├── schema/                 # Schema inspection
│   │   ├── execution/              # Query execution
│   │   ├── sp-management/          # SP lifecycle
│   │   └── transactions/           # Transaction control
│   ├── security/                   # Validation, audit logging
│   └── utils/                      # Version manager, helpers
├── test/                           # Test environment (Docker + SQL Server)
│   ├── docker-compose.yml          # SQL Server 2022 container
│   ├── setup.sh                    # Management script
│   ├── init-scripts/               # Database initialization
│   └── backups/                    # Database backups
├── .env.example                    # Configuration template
└── package.json

License

MIT

Contributing

Contributions are welcome! Please ensure all tools follow security best practices.