---
title: "Best Practices"
description: "Recommended patterns and anti-patterns for MCP configuration"
author: "Onli Platform"
date: "2024-01-01"
tags: ["mcp", "best-practices", "patterns", "optimization"]
---

# MCP Configuration Best Practices

This guide outlines recommended patterns, anti-patterns, and optimization strategies for MCP configuration.

## Configuration Management

### Recommended Patterns

#### Use Environment-Specific Configurations

```json
// config/development.json
{
  "onli-mcp": {
    "url": "https://stg.onli.app",
    "headers": {
      "User-Id": "${ONLI_DEV_USER_ID}",
      "App-Key": "${ONLI_DEV_APP_KEY}",
      "App-Symbol": "ENGMA"
    },
    "options": {
      "debug": true,
      "timeout": 30000
    }
  }
}
```

#### Implement Configuration Validation

```javascript
function validateConfig(config) {
  const required = ['url', 'headers.User-Id', 'headers.App-Key', 'headers.App-Symbol'];
  
  for (const field of required) {
    if (!getNestedValue(config, field)) {
      throw new Error(`Missing required field: ${field}`);
    }
  }
  
  return true;
}
```

#### Use Configuration Factories

```javascript
class MCPConfigFactory {
  static createConfig(environment) {
    const baseConfig = {
      headers: {
        'User-Id': process.env.ONLI_USER_ID,
        'App-Key': process.env.ONLI_APP_KEY,
        'App-Symbol': process.env.ONLI_APP_SYMBOL || 'ENGMA'
      }
    };

    switch (environment) {
      case 'development':
        return {
          ...baseConfig,
          url: 'https://stg.onli.app',
          options: { debug: true, timeout: 30000 }
        };
      case 'production':
        return {
          ...baseConfig,
          url: 'https://api.onli.app',
          options: { debug: false, timeout: 15000 }
        };
      default:
        throw new Error(`Unknown environment: ${environment}`);
    }
  }
}
```

### Anti-Patterns to Avoid

#### Hardcoding Credentials

```javascript
// DON'T DO THIS
const config = {
  "onli-mcp": {
    "url": "https://api.onli.app",
    "headers": {
      "User-Id": "user_12345_hardcoded",  // Never hardcode
      "App-Key": "ak_secret_key_123",     // Security risk
      "App-Symbol": "ENGMA"
    }
  }
};
```

#### Single Configuration for All Environments

```javascript
// DON'T DO THIS - Use environment-specific configs
const oneConfigForAll = {
  url: "https://api.onli.app",  // Should vary by environment
  debug: true                   // Should be false in production
};
```

#### Missing Error Handling

```javascript
// DON'T DO THIS
const client = new MCPClient(config);  // No validation or error handling
client.connect();                      // No error handling
```

## Security Best Practices

### Credential Management

#### Use Environment Variables

```bash
# .env.development
ONLI_USER_ID=dev_user_12345
ONLI_APP_KEY=ak_dev_secret_key
ONLI_APP_SYMBOL=ENGMA

# .env.production
ONLI_USER_ID=prod_user_67890
ONLI_APP_KEY=ak_prod_secret_key
ONLI_APP_SYMBOL=ENGMA
```

#### Implement Credential Rotation

```javascript
class CredentialManager {
  constructor() {
    this.refreshInterval = 24 * 60 * 60 * 1000; // 24 hours
    this.setupRotation();
  }

  async rotateCredentials() {
    const newCredentials = await this.fetchNewCredentials();
    this.updateConfig(newCredentials);
    this.scheduleNextRotation();
  }

  setupRotation() {
    setInterval(() => {
      this.rotateCredentials();
    }, this.refreshInterval);
  }
}
```

#### Monitor API Usage

```javascript
class APIMonitor {
  trackRequest(endpoint, method, timestamp) {
    // Log API usage patterns
    console.log(`API Call: ${method} ${endpoint} at ${timestamp}`);
    
    // Check for unusual patterns
    this.detectAnomalies(endpoint, method);
  }

  detectAnomalies(endpoint, method) {
    // Implement anomaly detection logic
    const recentCalls = this.getRecentCalls(endpoint, 5 * 60 * 1000); // 5 minutes
    
    if (recentCalls.length > this.thresholds[endpoint]) {
      this.alertSuspiciousActivity(endpoint, recentCalls.length);
    }
  }
}
```

### Network Security

#### Always Use HTTPS

```javascript
const config = {
  url: "https://api.onli.app",  // Always HTTPS
  options: {
    rejectUnauthorized: true,   // Verify SSL certificates
    secureProtocol: 'TLSv1_2_method'  // Use secure protocols
  }
};
```

#### Implement Request Signing

```javascript
class SecureClient {
  signRequest(request) {
    const timestamp = Date.now();
    const signature = this.generateSignature(request, timestamp);
    
    return {
      ...request,
      headers: {
        ...request.headers,
        'X-Timestamp': timestamp,
        'X-Signature': signature
      }
    };
  }
}
```

## Performance Optimization

### Connection Management

#### Connection Pooling

```javascript
const config = {
  "onli-mcp": {
    "url": "https://api.onli.app",
    "headers": {
      "User-Id": "${ONLI_USER_ID}",
      "App-Key": "${ONLI_APP_KEY}",
      "App-Symbol": "ENGMA"
    },
    "options": {
      "pooling": {
        "maxConnections": 10,
        "keepAlive": true,
        "keepAliveMsecs": 30000
      }
    }
  }
};
```

#### Appropriate Timeouts

```javascript
const timeoutConfig = {
  development: {
    connectionTimeout: 10000,
    requestTimeout: 30000,
    retryDelay: 2000
  },
  production: {
    connectionTimeout: 5000,
    requestTimeout: 15000,
    retryDelay: 1000
  }
};
```

### Retry Strategies

#### Exponential Backoff

```javascript
class RetryManager {
  async executeWithRetry(operation, maxRetries = 3) {
    let attempt = 0;
    
    while (attempt < maxRetries) {
      try {
        return await operation();
      } catch (error) {
        if (!this.isRetryableError(error) || attempt === maxRetries - 1) {
          throw error;
        }
        
        const delay = Math.pow(2, attempt) * 1000; // Exponential backoff
        await this.sleep(delay);
        attempt++;
      }
    }
  }

  isRetryableError(error) {
    return error.code === 'TIMEOUT' || 
           error.code === 'NETWORK_ERROR' ||
           (error.status >= 500 && error.status < 600);
  }
}
```

## Error Handling

### Comprehensive Error Handling

```javascript
class MCPErrorHandler {
  handleError(error, context) {
    switch (error.type) {
      case 'AUTHENTICATION_ERROR':
        this.handleAuthError(error, context);
        break;
      case 'NETWORK_ERROR':
        this.handleNetworkError(error, context);
        break;
      case 'TIMEOUT_ERROR':
        this.handleTimeoutError(error, context);
        break;
      default:
        this.handleGenericError(error, context);
    }
  }

  handleAuthError(error, context) {
    // Log security event
    this.logSecurityEvent('auth_failure', { error, context });
    
    // Attempt credential refresh
    this.refreshCredentials();
    
    // Notify administrators
    this.notifyAdmins('Authentication failure detected');
  }
}
```

### Circuit Breaker Pattern

```javascript
class CircuitBreaker {
  constructor(threshold = 5, timeout = 60000) {
    this.failureThreshold = threshold;
    this.timeout = timeout;
    this.failureCount = 0;
    this.state = 'CLOSED'; // CLOSED, OPEN, HALF_OPEN
    this.lastFailureTime = null;
  }

  async execute(operation) {
    if (this.state === 'OPEN') {
      if (Date.now() - this.lastFailureTime > this.timeout) {
        this.state = 'HALF_OPEN';
      } else {
        throw new Error('Circuit breaker is OPEN');
      }
    }

    try {
      const result = await operation();
      this.onSuccess();
      return result;
    } catch (error) {
      this.onFailure();
      throw error;
    }
  }
}
```

## Monitoring and Logging

### Structured Logging

```javascript
const logger = {
  logMCPOperation(operation, duration, success, metadata = {}) {
    const logEntry = {
      timestamp: new Date().toISOString(),
      operation,
      duration,
      success,
      environment: process.env.NODE_ENV,
      ...metadata
    };

    if (success) {
      console.log('MCP_SUCCESS', JSON.stringify(logEntry));
    } else {
      console.error('MCP_FAILURE', JSON.stringify(logEntry));
    }
  }
};
```

### Health Checks

```javascript
class HealthChecker {
  async performHealthCheck() {
    const checks = [
      this.checkConnectivity(),
      this.checkAuthentication(),
      this.checkLatency()
    ];

    const results = await Promise.allSettled(checks);
    
    return {
      healthy: results.every(r => r.status === 'fulfilled'),
      checks: results.map((r, i) => ({
        name: ['connectivity', 'authentication', 'latency'][i],
        status: r.status,
        value: r.value,
        error: r.reason
      }))
    };
  }
}
```

## Testing Best Practices

### Mock External Dependencies

```javascript
// test/mcp-client.test.js
describe('MCP Client', () => {
  beforeEach(() => {
    nock('https://stg.onli.app')
      .get('/health')
      .reply(200, { status: 'healthy' });
  });

  it('should connect successfully with valid config', async () => {
    const config = createTestConfig();
    const client = new MCPClient(config);
    
    const result = await client.healthCheck();
    expect(result.status).toBe('healthy');
  });
});
```

### Test Different Environments

```javascript
const testConfigs = {
  development: createDevConfig(),
  staging: createStagingConfig(),
  production: createProdConfig()
};

Object.entries(testConfigs).forEach(([env, config]) => {
  describe(`${env} environment`, () => {
    it('should have valid configuration', () => {
      expect(() => validateConfig(config)).not.toThrow();
    });
  });
});
```

## Next Steps

- Review [Setup Instructions](/mcp-configuration/setup) for implementation details
- Check [Troubleshooting Guide](/mcp-configuration/troubleshooting) for common issues
- Join our [Developer Community](https://forum.onli.app) for best practice discussions

## Support

For questions about best practices:

- **Email**: [support@onli.one](mailto:support@onli.one)
- **Documentation**: [Configuration Guides](/mcp-configuration/guides)
- **Community**: [Onli Developer Forum](https://forum.onli.app)