https://api.example.com/v1/mcp
http://localhost:3000/mcp

ws://hostname:port/mcp
wss://hostname:port/mcp

http://hostname:port/mcp/events
https://hostname:port/mcp/events

https://api.example.com/v1/mcp

{
  "name": "Authorization",
  "value": "Bearer your-api-token",
  "description": "API authentication token",
  "is_required": true,
  "is_secret": true
}

{
  "name": "X-API-Key",
  "value": "your-api-key",
  "description": "Service API key",
  "is_required": true,
  "is_secret": true
}

{
  "transport_type": "streamable",
  "url": "https://mcp-api.yourcompany.com/v1/mcp",
  "headers": [
    {
      "name": "Authorization",
      "value": "Bearer prod_token_xyz123",
      "description": "Production API authentication",
      "is_required": true,
      "is_secret": true
    },
    {
      "name": "X-Client-Version",
      "value": "1.0.0",
      "description": "Client version identifier",
      "is_required": false,
      "is_secret": false
    }
  ]
}

{
  "transport_type": "streamable",
  "url": "http://localhost:3000/mcp",
  "headers": [
    {
      "name": "X-Environment",
      "value": "development",
      "description": "Environment identifier",
      "is_required": false,
      "is_secret": false
    }
  ]
}

// Token-based authentication
const authenticateToken = async (token) => {
  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    return { valid: true, user: decoded };
  } catch (error) {
    return { valid: false, error: error.message };
  }
};

// API key authentication
const authenticateApiKey = async (apiKey) => {
  const validKeys = await loadValidApiKeys();
  return validKeys.includes(apiKey);
};

// Custom authentication middleware
server.setAuthenticationHandler(async (request) => {
  const authHeader = request.headers.authorization;
  
  if (!authHeader) {
    throw new Error('Authentication required');
  }
  
  if (authHeader.startsWith('Bearer ')) {
    const token = authHeader.substring(7);
    const result = await authenticateToken(token);
    if (!result.valid) {
      throw new Error('Invalid token');
    }
    return result.user;
  }
  
  if (authHeader.startsWith('ApiKey ')) {
    const apiKey = authHeader.substring(7);
    const isValid = await authenticateApiKey(apiKey);
    if (!isValid) {
      throw new Error('Invalid API key');
    }
    return { apiKey };
  }
  
  throw new Error('Unsupported authentication method');
});

// Security middleware example
import rateLimit from 'express-rate-limit';
import helmet from 'helmet';

// Rate limiting
const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // limit each IP to 100 requests per windowMs
  message: 'Too many requests from this IP'
});

// Security headers
app.use(helmet({
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      connectSrc: ["'self'", "wss:"]
    }
  }
}));

app.use('/mcp', limiter);

// Input validation
server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;
  
  // Validate tool name
  if (!/^[a-zA-Z0-9_-]+$/.test(name)) {
    throw new Error('Invalid tool name format');
  }
  
  // Validate arguments
  const validated = await validateToolArguments(name, args);
  if (!validated.valid) {
    throw new Error(`Invalid arguments: ${validated.error}`);
  }
  
  return await executeTool(name, validated.args);
});

// Load balancer configuration example
const servers = [
  'https://mcp-server-1.com:8080',
  'https://mcp-server-2.com:8080',
  'https://mcp-server-3.com:8080'
];

class LoadBalancedMCPClient {
  constructor(serverUrls) {
    this.servers = serverUrls;
    this.currentIndex = 0;
    this.clients = new Map();
  }
  
  async getClient() {
    const serverUrl = this.servers[this.currentIndex];
    
    if (!this.clients.has(serverUrl)) {
      const client = new Client({
        name: 'load-balanced-client',
        version: '1.0.0'
      }, { capabilities: {} });
      
      const transport = new HTTPClientTransport({
        baseUrl: serverUrl,
        timeout: 10000
      });
      
      await client.connect(transport);
      this.clients.set(serverUrl, client);
    }
    
    // Round-robin selection
    this.currentIndex = (this.currentIndex + 1) % this.servers.length;
    
    return this.clients.get(serverUrl);
  }
  
  async callTool(name, arguments) {
    const maxRetries = 3;
    let lastError;
    
    for (let i = 0; i < maxRetries; i++) {
      try {
        const client = await this.getClient();
        return await client.callTool({ name, arguments });
      } catch (error) {
        lastError = error;
        console.warn(`Server failed, trying next: ${error.message}`);
      }
    }
    
    throw new Error(`All servers failed: ${lastError.message}`);
  }
}

# Dockerfile for MCP server
FROM node:18-slim

WORKDIR /app

# Install dependencies
COPY package*.json ./
RUN npm ci --only=production

# Copy application code
COPY . .

# Create non-root user
RUN useradd -m -u 1001 mcpuser
RUN chown -R mcpuser:mcpuser /app
USER mcpuser

# Expose port
EXPOSE 8080

# Health check
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1

# Start server
CMD ["node", "dist/server.js"]

# docker-compose.yml for multiple instances
version: '3.8'
services:
  mcp-server-1:
    build: .
    ports:
      - "8081:8080"
    environment:
      - NODE_ENV=production
      - SERVER_ID=server-1
    restart: unless-stopped
    
  mcp-server-2:
    build: .
    ports:
      - "8082:8080"
    environment:
      - NODE_ENV=production
      - SERVER_ID=server-2
    restart: unless-stopped
    
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
      - ./ssl:/etc/nginx/ssl
    depends_on:
      - mcp-server-1
      - mcp-server-2
    restart: unless-stopped

// Health check endpoint
server.addHealthCheck('/health', async () => {
  const checks = {
    server: 'healthy',
    database: await checkDatabase(),
    externalServices: await checkExternalServices(),
    memory: process.memoryUsage(),
    uptime: process.uptime()
  };
  
  const allHealthy = Object.values(checks)
    .filter(v => typeof v === 'string')
    .every(status => status === 'healthy');
  
  return {
    status: allHealthy ? 'healthy' : 'unhealthy',
    timestamp: new Date().toISOString(),
    checks
  };
});

// Readiness check for load balancers
server.addHealthCheck('/ready', async () => {
  const isReady = await checkServerReadiness();
  return {
    status: isReady ? 'ready' : 'not-ready',
    timestamp: new Date().toISOString()
  };
});

// Prometheus metrics example
import prometheus from 'prom-client';

const requestCounter = new prometheus.Counter({
  name: 'mcp_requests_total',
  help: 'Total number of MCP requests',
  labelNames: ['method', 'status']
});

const requestDuration = new prometheus.Histogram({
  name: 'mcp_request_duration_seconds',
  help: 'Duration of MCP requests',
  labelNames: ['method']
});

const activeConnections = new prometheus.Gauge({
  name: 'mcp_active_connections',
  help: 'Number of active MCP connections'
});

// Instrument request handling
server.onRequest(async (request, response) => {
  const startTime = Date.now();
  const method = request.method;
  
  try {
    const result = await handleRequest(request);
    requestCounter.inc({ method, status: 'success' });
    return result;
  } catch (error) {
    requestCounter.inc({ method, status: 'error' });
    throw error;
  } finally {
    const duration = (Date.now() - startTime) / 1000;
    requestDuration.observe({ method }, duration);
  }
});

// Expose metrics endpoint
server.addRoute('/metrics', async (req, res) => {
  res.set('Content-Type', prometheus.register.contentType);
  res.end(await prometheus.register.metrics());
});

# Test server connectivity
curl -v https://your-mcp-server.com:8080/health

# WebSocket connection testing
wscat -c wss://your-mcp-server.com:8080/mcp

# MCP protocol testing
npx @modelcontextprotocol/inspector http https://your-mcp-server.com:8080/mcp

# Load testing
npx autocannon -c 10 -d 30 https://your-mcp-server.com:8080/mcp

// Edge-optimized MCP server
const edgeServer = new Server({
  name: 'edge-mcp-server',
  version: '1.0.0'
}, {
  capabilities: {
    resources: {},
    tools: {},
    // Enable caching for edge deployment
    caching: {
      enabled: true,
      ttl: 300,
      regions: ['us-east-1', 'eu-west-1', 'ap-southeast-1']
    }
  }
});

// Implement geo-aware resource routing
server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
  const clientRegion = request.headers['cf-ipcountry'] || 'US';
  const nearestCache = await findNearestCache(clientRegion);
  
  return await nearestCache.getResource(request.params.uri);
});