@iflow-mcp/boilerplate-mcp-server

Boilerplate MCP Server

A production-ready foundation for developing custom Model Context Protocol (MCP) servers in TypeScript. Provides a complete layered architecture pattern, working example implementation, and comprehensive developer infrastructure to connect AI assistants with external APIs and data sources.

Features

• Dual Transport Support: STDIO and Streamable HTTP transports with automatic fallback
• 5-Layer Architecture: Clean separation between CLI, tools, controllers, services, and utilities
• Type Safety: Full TypeScript implementation with Zod schema validation
• Complete IP Address Example: Tools, resources, and CLI commands for IP geolocation
• Comprehensive Testing: Unit and integration tests with coverage reporting
• Production Tooling: ESLint, Prettier, semantic-release, and MCP Inspector integration
• Error Handling: Structured error handling with contextual logging

What is MCP?

Model Context Protocol (MCP) is an open standard for securely connecting AI systems to external tools and data sources. This boilerplate implements the MCP specification with a clean, layered architecture that can be extended to build custom MCP servers for any API or data source.

Prerequisites

• Node.js (>=18.x): Download
• Git: For version control

Quick Start

# Clone the repository
git clone https://github.com/aashari/boilerplate-mcp-server.git
cd boilerplate-mcp-server

# Install dependencies
npm install

# Build the project
npm run build

# Run in different modes:

# 1. CLI Mode - Execute commands directly
npm run cli -- get-ip-details 8.8.8.8
npm run cli -- get-ip-details              # Get your current IP
npm run cli -- get-ip-details 1.1.1.1 --include-extended-data

# 2. STDIO Transport - For AI assistant integration (Claude Desktop, Cursor)
npm run mcp:stdio

# 3. HTTP Transport - For web-based integrations
npm run mcp:http

# 4. Development with MCP Inspector
npm run mcp:inspect                         # Auto-opens browser with debugging UI

Transport Modes

STDIO Transport

• JSON-RPC communication via stdin/stdout
• Used by Claude Desktop, Cursor AI, and other local AI assistants
• Run with: TRANSPORT_MODE=stdio node dist/index.js

Streamable HTTP Transport

• HTTP-based transport with Server-Sent Events (SSE)
• Supports multiple concurrent connections and web integrations
• Runs on port 3000 by default (configurable via PORT env var)
• MCP Endpoint: http://localhost:3000/mcp
• Health Check: http://localhost:3000/ → Returns server version
• Run with: TRANSPORT_MODE=http node dist/index.js

Architecture Overview

Project Structure (Click to expand)

src/
├── cli/                    # Command-line interfaces
│   ├── index.ts            # CLI entry point with Commander setup
│   └── ipaddress.cli.ts    # IP address CLI commands
├── controllers/            # Business logic orchestration  
│   ├── ipaddress.controller.ts    # IP lookup business logic
│   └── ipaddress.formatter.ts     # Response formatting
├── services/               # External API interactions
│   ├── vendor.ip-api.com.service.ts  # ip-api.com service
│   └── vendor.ip-api.com.types.ts    # Service type definitions
├── tools/                  # MCP tool definitions (AI interface)
│   ├── ipaddress.tool.ts   # IP lookup tool for AI assistants
│   └── ipaddress.types.ts  # Tool argument schemas
├── resources/              # MCP resource definitions
│   └── ipaddress.resource.ts # IP lookup resource (URI: ip://address)
├── types/                  # Global type definitions
│   └── common.types.ts     # Shared interfaces (ControllerResponse, etc.)
├── utils/                  # Shared utilities
│   ├── logger.util.ts      # Contextual logging system
│   ├── error.util.ts       # MCP-specific error formatting
│   ├── error-handler.util.ts # Error handling utilities
│   ├── config.util.ts      # Environment configuration
│   ├── constants.util.ts   # Version and package constants
│   ├── formatter.util.ts   # Markdown formatting
│   └── transport.util.ts   # HTTP transport utilities
└── index.ts                # Server entry point (dual transport)

5-Layer Architecture

The boilerplate follows a clean, layered architecture that promotes maintainability and clear separation of concerns:

1. CLI Layer (src/cli/)

• Purpose: Command-line interfaces for direct tool usage and testing
• Implementation: Commander-based argument parsing with contextual error handling
• Example: get-ip-details [ipAddress] --include-extended-data --no-use-https
• Pattern: Register commands → Parse arguments → Call controllers → Handle errors

2. Tools Layer (src/tools/)

• Purpose: MCP tool definitions that AI assistants can invoke
• Implementation: Zod schema validation with structured responses
• Example: ip_get_details tool with optional IP address and configuration options
• Pattern: Define schema → Validate args → Call controller → Format MCP response

3. Resources Layer (src/resources/)

• Purpose: MCP resources providing contextual data accessible via URIs
• Implementation: Resource handlers that respond to URI-based requests
• Example: ip://8.8.8.8 resource providing IP geolocation data
• Pattern: Register URI patterns → Parse requests → Return formatted content

4. Controllers Layer (src/controllers/)

• Purpose: Business logic orchestration with comprehensive error handling
• Implementation: Options validation, fallback logic, response formatting
• Example: IP lookup with HTTPS fallback, test environment detection, API token validation
• Pattern: Validate inputs → Apply defaults → Call services → Format responses

5. Services Layer (src/services/)

• Purpose: Direct external API interactions with minimal business logic
• Implementation: HTTP transport utilities with structured error handling
• Example: ip-api.com API calls with authentication and field selection
• Pattern: Build requests → Make API calls → Validate responses → Return raw data

6. Utils Layer (src/utils/)

• Purpose: Shared functionality across all layers
• Key Components:
  • logger.util.ts: Contextual logging (file:method context)
  • error.util.ts: MCP-specific error formatting
  • transport.util.ts: HTTP/API utilities with retry logic
  • config.util.ts: Environment configuration management

Developer Guide

Development Scripts

# Build and Clean
npm run build               # Build TypeScript to dist/
npm run clean               # Remove dist/ and coverage/
npm run prepare             # Build + ensure executable permissions (for npm publish)

# CLI Testing
npm run cli -- get-ip-details 8.8.8.8                    # Test specific IP
npm run cli -- get-ip-details --include-extended-data    # Test with extended data
npm run cli -- get-ip-details --no-use-https             # Test with HTTP

# MCP Server Modes
npm run mcp:stdio           # STDIO transport for AI assistants
npm run mcp:http            # HTTP transport on port 3000
npm run mcp:inspect         # HTTP + auto-open MCP Inspector

# Development with Debugging
npm run dev:stdio           # STDIO with MCP Inspector integration
npm run dev:http            # HTTP with debug logging enabled

# Testing
npm test                    # Run all tests (Jest)
npm run test:coverage       # Generate coverage report
npm run test:cli            # Run CLI-specific tests

# Code Quality
npm run lint                # ESLint with TypeScript rules
npm run format              # Prettier formatting
npm run update:deps         # Update dependencies

Environment Variables

Core Configuration

• TRANSPORT_MODE: Transport mode (stdio | http, default: stdio)
• PORT: HTTP server port (default: 3000)
• DEBUG: Enable debug logging (true | false, default: false)

IP API Configuration

• IPAPI_API_TOKEN: API token for ip-api.com extended data (optional, free tier available)

Example .env File

# Basic configuration
TRANSPORT_MODE=http
PORT=3001
DEBUG=true

# Extended data (requires ip-api.com account)
IPAPI_API_TOKEN=your_token_here

Debugging Tools

• MCP Inspector: Visual tool for testing your MCP tools

  • Run server with npm run mcp:inspect
  • Open the URL shown in terminal
  • Test your tools interactively

• Debug Logging: Enable with DEBUG=true environment variable

Configuration (Click to expand)

Create ~/.mcp/configs.json:

{
  "boilerplate": {
    "environments": {
      "DEBUG": "true",
      "TRANSPORT_MODE": "http",
      "PORT": "3000"
    }
  }
}

Building Custom Tools

Step-by-Step Tool Implementation Guide (Click to expand)

1. Define Service Layer

Create a new service in src/services/ following the vendor-specific naming pattern:

// src/services/vendor.example-api.service.ts
import { Logger } from '../utils/logger.util.js';
import { fetchApi } from '../utils/transport.util.js';
import { ExampleApiResponse, ExampleApiRequestOptions } from './vendor.example-api.types.js';
import { createApiError, McpError } from '../utils/error.util.js';

const serviceLogger = Logger.forContext('services/vendor.example-api.service.ts');

async function get(
	param?: string,
	options: ExampleApiRequestOptions = {}
): Promise<ExampleApiResponse> {
	const methodLogger = serviceLogger.forMethod('get');
	methodLogger.debug(`Calling Example API with param: ${param}`);

	try {
		const url = `https://api.example.com/${param || 'default'}`;
		const rawData = await fetchApi<ExampleApiResponse>(url, {
			headers: options.apiKey ? { 'Authorization': `Bearer ${options.apiKey}` } : {}
		});

		methodLogger.debug('Received successful response from Example API');
		return rawData;
	} catch (error) {
		methodLogger.error('Service error fetching data', error);
		
		if (error instanceof McpError) {
			throw error;
		}
		
		throw createApiError(
			'Unexpected service error while fetching data',
			undefined,
			error
		);
	}
}

export default { get };

2. Create Controller

Add a controller in src/controllers/ to handle business logic with error context:

// src/controllers/example.controller.ts
import { Logger } from '../utils/logger.util.js';
import exampleService from '../services/vendor.example-api.service.js';
import { formatExample } from './example.formatter.js';
import { handleControllerError, buildErrorContext } from '../utils/error-handler.util.js';
import { ControllerResponse } from '../types/common.types.js';
import { config } from '../utils/config.util.js';

const logger = Logger.forContext('controllers/example.controller.ts');

export interface GetDataOptions {
	param?: string;
	includeMetadata?: boolean;
}

async function getData(
	options: GetDataOptions = {}
): Promise<ControllerResponse> {
	const methodLogger = logger.forMethod('getData');
	methodLogger.debug(`Getting data for param: ${options.param || 'default'}`, options);

	try {
		// Apply business logic and defaults
		const apiKey = config.get('EXAMPLE_API_TOKEN');
		
		// Call service layer
		const data = await exampleService.get(options.param, {
			apiKey,
			includeMetadata: options.includeMetadata ?? false
		});
		
		// Format response
		const formattedContent = formatExample(data);
		return { content: formattedContent };
		
	} catch (error) {
		throw handleControllerError(
			error,
			buildErrorContext(
				'ExampleData',
				'getData',
				'controllers/example.controller.ts@getData',
				options.param || 'default',
				{ options }
			)
		);
	}
}

export default { getData };

3. Implement MCP Tool

Create a tool definition in src/tools/ following the registration pattern:

// src/tools/example.tool.ts
import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { z } from 'zod';
import { Logger } from '../utils/logger.util.js';
import { formatErrorForMcpTool } from '../utils/error.util.js';
import exampleController from '../controllers/example.controller.js';

const logger = Logger.forContext('tools/example.tool.ts');

// Define Zod schema for tool arguments
const GetDataSchema = z.object({
	param: z.string().optional().describe('Optional parameter for the API call'),
	includeMetadata: z.boolean().optional().default(false)
		.describe('Whether to include additional metadata in the response')
});

async function handleGetData(args: Record<string, unknown>) {
	const methodLogger = logger.forMethod('handleGetData');
	
	try {
		methodLogger.debug('Tool example_get_data called', args);

		// Validate arguments with Zod
		const validatedArgs = GetDataSchema.parse(args);

		// Call controller
		const result = await exampleController.getData({
			param: validatedArgs.param,
			includeMetadata: validatedArgs.includeMetadata
		});

		// Return MCP-formatted response
		return {
			content: [
				{
					type: 'text' as const,
					text: result.content
				}
			]
		};
	} catch (error) {
		methodLogger.error('Tool example_get_data failed', error);
		return formatErrorForMcpTool(error);
	}
}

// Registration function following the pattern used by existing tools
function registerTools(server: McpServer) {
	const registerLogger = logger.forMethod('registerTools');
	registerLogger.debug('Registering example tools...');

	server.tool(
		'example_get_data',
		`Gets data from the Example API with optional parameter.
Use this tool to fetch example data. Returns formatted data as Markdown.`,
		GetDataSchema.shape,
		handleGetData
	);

	registerLogger.debug('Example tools registered successfully');
}

export default { registerTools };

4. Add CLI Support

Create a CLI command in src/cli/ following the Commander pattern:

// src/cli/example.cli.ts
import { Command } from 'commander';
import { Logger } from '../utils/logger.util.js';
import exampleController from '../controllers/example.controller.js';
import { handleCliError } from '../utils/error.util.js';

const logger = Logger.forContext('cli/example.cli.ts');

function register(program: Command) {
	const methodLogger = logger.forMethod('register');
	methodLogger.debug('Registering example CLI commands...');

	program
		.command('get-data')
		.description('Gets data from the Example API')
		.argument('[param]', 'Optional parameter for the API call')
		.option('-m, --include-metadata', 'Include additional metadata in response')
		.action(async (param, options) => {
			const actionLogger = logger.forMethod('action:get-data');
			
			try {
				actionLogger.debug('CLI get-data called', { param, options });

				const result = await exampleController.getData({
					param,
					includeMetadata: options.includeMetadata || false
				});

				console.log(result.content);
			} catch (error) {
				handleCliError(error);
			}
		});

	methodLogger.debug('Example CLI commands registered successfully');
}

export default { register };

5. Register Components

Update the entry points to register your new components:

// 1. Register CLI in src/cli/index.ts
import exampleCli from './example.cli.js';

export async function runCli(args: string[]) {
	// ... existing setup code ...
	
	// Register CLI commands
	exampleCli.register(program);  // Add this line
	
	// ... rest of function
}

// 2. Register Tools in src/index.ts
import exampleTools from './tools/example.tool.js';

// In the startServer function, after existing registrations:
exampleTools.registerTools(serverInstance);

IP Address Example Implementation

The boilerplate includes a complete IP address geolocation example demonstrating all layers:

Available Tools & Commands

CLI Commands:

npm run cli -- get-ip-details                           # Get current public IP
npm run cli -- get-ip-details 8.8.8.8                  # Get details for specific IP
npm run cli -- get-ip-details 1.1.1.1 --include-extended-data   # With extended data
npm run cli -- get-ip-details 8.8.8.8 --no-use-https   # Force HTTP (for free tier)

MCP Tools:

• ip_get_details - IP geolocation lookup for AI assistants

MCP Resources:

• ip:// - Current IP details
• ip://8.8.8.8 - Specific IP details

Features Demonstrated

• Fallback Logic: HTTPS → HTTP fallback for free tier users
• Environment Detection: Different behavior in test vs production
• API Token Support: Optional token for extended data (ASN, mobile detection, etc.)
• Error Handling: Structured errors for private/reserved IP addresses
• Response Formatting: Clean Markdown output with geolocation data

Configuration Options

# Optional - for extended data features
IPAPI_API_TOKEN=your_token_from_ip-api.com

# Development
DEBUG=true                    # Enable detailed logging
TRANSPORT_MODE=http          # Use HTTP transport
PORT=3001                    # Custom port

Publishing Your MCP Server

• Customize Package Details:

  {
    "name": "your-mcp-server-name",
    "version": "1.0.0", 
    "description": "Your custom MCP server",
    "author": "Your Name",
    "keywords": ["mcp", "your-domain", "ai-integration"]
  }
  

• Update Documentation: Replace IP address examples with your use case

• Test Thoroughly:

  npm run build && npm test
  npm run cli -- your-command
  npm run mcp:stdio    # Test with MCP Inspector
  

• Publish: npm publish (requires npm login)

Testing Strategy

The boilerplate includes comprehensive testing infrastructure:

Test Structure

tests/               # Not present - tests are in src/
src/
├── **/*.test.ts     # Co-located with source files
├── utils/           # Utility function tests
├── controllers/     # Business logic tests  
├── services/        # API integration tests
└── cli/             # CLI command tests

Testing Best Practices

• Unit Tests: Test utilities and pure functions (*.util.test.ts)
• Controller Tests: Test business logic with mocked service calls
• Service Tests: Test API integration with real/mocked HTTP calls
• CLI Tests: Test command parsing and execution
• Test Environment Detection: Automatic test mode handling in controllers

Running Tests

npm test                    # Run all tests
npm run test:coverage       # Generate coverage report  
npm run test:cli           # CLI-specific tests only

Coverage Goals

• Target: >80% test coverage
• Focus on business logic (controllers) and utilities
• Mock external services appropriately

License

ISC License

Resources & Documentation

MCP Protocol Resources

• MCP Specification
• MCP SDK Documentation
• MCP Inspector - Visual debugging tool

Implementation References

• Anthropic MCP Announcement
• Awesome MCP Servers - Community examples
• TypeScript Documentation

Your MCP Server Ecosystem

• All @aashari MCP Servers - NPM packages
• GitHub Repositories - Source code