SQL Server MCP Service

A secure and robust Model Context Protocol (MCP) service for executing SQL Server queries via MCP protocol. This service provides a safe way to interact with SQL Server databases while preventing destructive operations and SQL injection attacks.

🚀 Features

• 🔒 Secure Query Execution: Built-in protection against SQL injection and destructive operations
• 📊 Schema Discovery: Get table, function, and procedure schemas and database information
• 🛠️ Multiple Tools: 9 specialized tools for different database operations
• ⚡ High Performance: Connection pooling for efficient database operations
• 🔧 TypeScript Support: Full TypeScript implementation with type safety
• 🧪 Comprehensive Testing: Jest-based test suite for reliability

🛠️ Available Tools

1. execute_query

Executes safe SQL queries with parameter support.

Parameters:

• query (string, required): The SQL query to execute
• parameters (object, optional): Query parameters for prepared statements

Example:

{
  "query": "SELECT * FROM Users WHERE Status = @status",
  "parameters": {
    "status": "active"
  }
}

2. get_table_schema

Retrieves detailed column information for a specific table.

Parameters:

• tableName (string, required): Name of the table
• schemaName (string, optional): Schema name (default: "dbo")

Example:

{
  "tableName": "Users",
  "schemaName": "dbo"
}

3. list_tables

Lists all tables in the database with optional schema filtering.

Parameters:

• schemaName (string, optional): Filter tables by specific schema

Example:

{
  "schemaName": "dbo"
}

4. get_database_info

Retrieves general database information (name, version, edition, etc.).

Parameters: None

5. list_procedures

Lists all stored procedures in the database, optionally filtered by schema.

Parameters:

• schemaName (string, optional): Filter procedures by schema

Example:

{
  "schemaName": "dbo"
}

6. list_functions

Lists all functions (scalar and table-valued) in the database, optionally filtered by schema and function type.

Parameters:

• schemaName (string, optional): Filter functions by schema
• functionType (string, optional): 'SCALAR' or 'TABLE'

Example:

{
  "schemaName": "dbo",
  "functionType": "SCALAR"
}

7. get_procedure_schema

Gets the schema and parameters of a specific stored procedure.

Parameters:

• procedureName (string, required): Name of the procedure
• schemaName (string, optional): Schema name (default: "dbo")

Example:

{
  "procedureName": "MyProcedure",
  "schemaName": "dbo"
}

8. get_function_schema

Gets the schema and parameters of a specific function.

Parameters:

• functionName (string, required): Name of the function
• schemaName (string, optional): Schema name (default: "dbo")

Example:

{
  "functionName": "MyFunction",
  "schemaName": "dbo"
}

9. execute_procedure

Executes a stored procedure with parameters.

Parameters:

• procedureName (string, required): Name of the procedure
• parameters (object, optional): Procedure parameters
• schemaName (string, optional): Schema name (default: "dbo")

Example:

{
  "procedureName": "MyProcedure",
  "parameters": {
    "param1": 123,
    "param2": "abc"
  },
  "schemaName": "dbo"
}

📦 Installation

Prerequisites

• Node.js >= 20.0.0
• SQL Server instance
• pnpm (recommended)

Install Dependencies

pnpm install

⚙️ Configuration

1. Copy Environment Template

cp .env.example .env

2. Configure Environment Variables

Example .env:

HTTP_PORT=3333
NODE_ENV=development
ORIGIN=http://localhost:3000,http://example.com
SQL_SERVER=localhost
SQL_DATABASE=master
SQL_USER=sa
SQL_PASSWORD=YourSecurePassword123!
SQL_PORT=1433
SQL_ENCRYPT=true
SQL_TRUST_CERT=false

🚀 Usage

Start HTTP Server (Recommended)

pnpm run dev:http
# or
pnpm run start:http

Build for Production

pnpm run build

Running Tests

pnpm run test

🖥️ Desktop App Integration

To integrate this server with a desktop app, add the following to your app's server configuration:

Using Node.js directly:

{
  "mcpServers": {
    "sqlserver": {
      "command": "node",
      "args": [
        "{ABSOLUTE PATH TO FILE HERE}/dist/cli.js"
      ]
    }
  }
}

Using npx:

{
  "mcpServers": {
    "sqlserver": {
      "command": "npx",
      "args": [
        "mcp-mssql-server"
      ]
    }
  }
}

Note: Replace {ABSOLUTE PATH TO FILE HERE} with the actual absolute path to your project's dist/cli.js file.

🤖 OpenAI Integration

To use this MCP server with OpenAI's API, you can integrate it using the MCP protocol. Here's an example:

import OpenAI from "openai";
const client = new OpenAI();

const resp = await client.responses.create({
  model: "gpt-5",
  tools: [
    {
      type: "mcp",
      server_label: "mssql",
      server_description: "A SQL Server MCP server for executing safe database queries and schema discovery.",
      server_url: "http://localhost:3333/mcp",
      require_approval: "never",
    },
  ],
  input: "Show me all tables in the database",
});

console.log(resp.output_text);

Note: Make sure your HTTP server is running on the specified port before making requests to OpenAI.

🔒 Security Features

Query Validation

The service automatically blocks potentially destructive operations:

• ❌ DROP TABLE
• ❌ DELETE FROM
• ❌ TRUNCATE TABLE
• ❌ INSERT INTO
• ❌ UPDATE
• ❌ CREATE TABLE
• ❌ ALTER TABLE
• ❌ Stored procedures (sp_, xp_)
• ❌ SQL injection patterns
• ❌ Comments (--, /* */)

Allowed Operations

• ✅ SELECT queries
• ✅ WITH clauses (CTEs)
• ✅ SHOW commands
• ✅ DESCRIBE commands
• ✅ EXPLAIN commands
• ✅ Safe EXEC/EXECUTE for procedures/functions

Parameter Sanitization

All query and procedure parameters are automatically sanitized to prevent injection attacks.

🧪 Testing

The project includes comprehensive tests for schema validation and core functionality:

# Run all tests
pnpm run test

# Run tests in watch mode
pnpm run test -- --watch

# Run tests with coverage
pnpm run test -- --coverage

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

👨‍💻 Author

Vinicius de Souza Santos

• Email: viniciuskt0@gmail.com
• GitHub: @vini-cius

🙏 Acknowledgments

• Model Context Protocol for the MCP specification
• mssql for SQL Server connectivity
• Zod for runtime type validation

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