SQL Server MCP Server (Node.js/TypeScript)

A Model Context Protocol (MCP) server for connecting to and querying Microsoft SQL Server databases, built with TypeScript and Node.js.

What is MCP?

MCP (Model Context Protocol) is an open protocol that allows AI assistants to securely and standardly interact with external data sources and tools. Through MCP servers, AI assistants can:

- Directly connect to databases to execute queries
- Call external APIs to get real-time data
- Access file systems and cloud storage
- Execute custom business logic

MCP architecture contains two core components:
- MCP Client: Built into AI assistants (like Claude Desktop), responsible for communicating with servers
- MCP Server: Independent processes that provide specific tools and data access capabilities

Features

- List all available databases
- List all tables in a specific database
- Get table structure information (columns, data types, primary keys, etc.)
- Execute safe SELECT queries (limited to 1000 rows)
- Get table index information
- Get table statistics (row count, size, etc.)
- Connection pool management for improved performance

Installation

$3

``bash
npm install -g @ggball/mcp-sqlserver
`

After global installation, the mcp-sqlserver command will be available system-wide.

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`bash
npx @ggball/mcp-sqlserver
`

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#### 1. System Requirements

- Node.js 18.0.0 or higher
- npm 9.0.0 or higher
- SQL Server (any version)

#### 2. Install Dependencies

`bash
npm install
`

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`bash
npm run build
`

Configuration

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Create a .env file or set the following environment variables:

| Environment Variable | Description | Default Value |
|---------------------|-------------|---------------|
| SQLSERVER_HOST | Server address | localhost |
| SQLSERVER_PORT | Port number | 1433 |
| SQLSERVER_USER | Username | sa |
| SQLSERVER_PASSWORD | Password | (empty) |
| SQLSERVER_DATABASE | Default database | master |
| SQLSERVER_ENCRYPT | Enable encryption | true |
| SQLSERVER_TRUST_SERVER_CERTIFICATE | Trust server certificate | true |

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`env
SQLSERVER_HOST=localhost
SQLSERVER_PORT=1433
SQLSERVER_USER=sa
SQLSERVER_PASSWORD=YourPassword123
SQLSERVER_DATABASE=MyDatabase
`

Usage

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`bash
npm start
`

Or for development with auto-rebuild:

`bash
npm run dev
`

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#### Config File Location

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

#### Option 1: Using Global Installation (Recommended)

If you installed the package globally:

`json
{
"mcpServers": {
"sqlserver": {
"command": "mcp-sqlserver",
"env": {
"SQLSERVER_HOST": "localhost",
"SQLSERVER_PORT": "1433",
"SQLSERVER_USER": "sa",
"SQLSERVER_PASSWORD": "YourPassword123",
"SQLSERVER_DATABASE": "MyDatabase"
}
}
}
}
`

#### Option 2: Using npx

`json
{
"mcpServers": {
"sqlserver": {
"command": "npx",
"args": ["@ggball/mcp-sqlserver"],
"env": {
"SQLSERVER_HOST": "localhost",
"SQLSERVER_PORT": "1433",
"SQLSERVER_USER": "sa",
"SQLSERVER_PASSWORD": "YourPassword123",
"SQLSERVER_DATABASE": "MyDatabase"
}
}
}
}
`

#### Option 3: From Source

`json
{
"mcpServers": {
"sqlserver": {
"command": "node",
"args": ["/path/to/mcp-sqlserver-npm/dist/index.js"],
"env": {
"SQLSERVER_HOST": "localhost",
"SQLSERVER_PORT": "1433",
"SQLSERVER_USER": "sa",
"SQLSERVER_PASSWORD": "YourPassword123",
"SQLSERVER_DATABASE": "MyDatabase"
}
}
}
}
`

Restart Claude Desktop after configuration.

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#### Config File Location

- macOS/Linux: ~/.config/claude-code/config.json
- Windows: %APPDATA%\claude-code\config.json

#### Option 1: Using Global Installation (Recommended)

`json
{
"mcpServers": {
"sqlserver": {
"command": "mcp-sqlserver",
"env": {
"SQLSERVER_HOST": "localhost",
"SQLSERVER_PORT": "1433",
"SQLSERVER_USER": "sa",
"SQLSERVER_PASSWORD": "YourPassword123",
"SQLSERVER_DATABASE": "MyDatabase"
}
}
}
}
`

#### Option 2: Using npx

`json
{
"mcpServers": {
"sqlserver": {
"command": "npx",
"args": ["@ggball/mcp-sqlserver"],
"env": {
"SQLSERVER_HOST": "localhost",
"SQLSERVER_PORT": "1433",
"SQLSERVER_USER": "sa",
"SQLSERVER_PASSWORD": "YourPassword123",
"SQLSERVER_DATABASE": "MyDatabase"
}
}
}
}
`

#### Option 3: From Source

`json
{
"mcpServers": {
"sqlserver": {
"command": "node",
"args": ["/path/to/mcp-sqlserver-npm/dist/index.js"],
"env": {
"SQLSERVER_HOST": "localhost",
"SQLSERVER_PORT": "1433",
"SQLSERVER_USER": "sa",
"SQLSERVER_PASSWORD": "YourPassword123",
"SQLSERVER_DATABASE": "MyDatabase"
}
}
}
}
`

Restart Claude Code after configuration.

Available Tools

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Lists all SQL Server databases (excluding system databases).

`
Tool name: list_databases
Parameters: None
`

Example:
`
List all available databases
`

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Lists all tables in a specific database.

`
Tool name: list_tables
Parameters:
- database (required): Database name
- schema (optional): Schema name, defaults to "dbo"
`

Example:
`
List all tables in MyDatabase
`

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Gets table structure information including columns, data types, nullable, primary keys, etc.

`
Tool name: describe_table
Parameters:
- database (required): Database name
- table (required): Table name
- schema (optional): Schema name, defaults to "dbo"
`

Example:
`
Show the structure of the Users table in MyDatabase
`

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Executes SQL SELECT queries (only SELECT and WITH allowed, limited to 1000 rows).

`
Tool name: execute_query
Parameters:
- query (required): SQL query statement
- database (optional): Database name, defaults to configured database
`

Example:
`
Query users older than 18 from the Users table
`

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Gets index information for a table.

`
Tool name: get_table_indexes
Parameters:
- database (required): Database name
- table (required): Table name
- schema (optional): Schema name, defaults to "dbo"
`

Example:
`
Get index information for the Users table
`

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Gets table statistics including row count and storage size.

`
Tool name: get_table_stats
Parameters:
- database (required): Database name
- table (required): Table name
- schema (optional): Schema name, defaults to "dbo"
`

Example:
`
Get statistics for the Users table
`

Usage Examples

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`
You: List all available databases
Claude: [calls list_databases] ...

You: Show what tables are in MyDatabase
Claude: [calls list_tables] ...
`

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`
You: Query the last 10 orders from Orders table
Claude: [calls describe_table to understand table structure]
[calls execute_query to perform query] ...
`

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`
You: Analyze the structure and indexes of Users table
Claude: [calls describe_table]
[calls get_table_indexes]
[calls get_table_stats] ...
`

Security Notes

- execute_query tool only allows SELECT and WITH queries
- Automatically blocks statements containing dangerous keywords (DROP, DELETE, UPDATE, etc.)
- Query results are limited to 1000 rows

Development

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`
mcp-sqlserver-npm/
├── src/
│ ├── index.ts # Main server entry point
│ ├── config.ts # Configuration management
│ └── connection.ts # Connection pool implementation
├── dist/ # Compiled output
├── package.json
├── tsconfig.json
└── README.md
`

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- npm run build - Compile TypeScript
- npm run dev - Compile and run in development mode
- npm start - Run the compiled server
- npm run watch - Watch mode for TypeScript compilation

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- @modelcontextprotocol/sdk - Official MCP SDK for TypeScript
- tedious - SQL Server connector for Node.js
- zod - Schema validation
- dotenv` - Environment variable management

License

MIT License

Sources

- MCP TypeScript SDK GitHub
- NPM Package: @modelcontextprotocol/sdk
- GitHub Repository
- 掘金 - MCP TypeScript SDK 核心概念
- Mojotv.cn - MCP TypeScript SDK 教程