---

name: retellai-reliability-patterns description: | Implement Retell AI reliability patterns including circuit breakers, idempotency, and graceful degradation. Use when building fault-tolerant Retell AI integrations, implementing retry strategies, or adding resilience to production Retell AI services. Trigger with phrases like "retellai reliability", "retellai circuit breaker", "retellai idempotent", "retellai resilience", "retellai fallback", "retellai bulkhead". allowed-tools: Read, Write, Edit version: 1.0.0 license: MIT author: Jeremy Longshore jeremy@intentsolutions.io

Retell AI Reliability Patterns

Overview

Production-grade reliability patterns for Retell AI integrations.

Prerequisites

• Understanding of circuit breaker pattern
• opossum or similar library installed
• Queue infrastructure for DLQ
• Caching layer for fallbacks

Circuit Breaker

Copyimport CircuitBreaker from 'opossum';

const retellaiBreaker = new CircuitBreaker(
  async (operation: () => Promise<any>) => operation(),
  {
    timeout: 30000,
    errorThresholdPercentage: 50,
    resetTimeout: 30000,
    volumeThreshold: 10,
  }
);

// Events
retellaiBreaker.on('open', () => {
  console.warn('Retell AI circuit OPEN - requests failing fast');
  alertOps('Retell AI circuit breaker opened');
});

retellaiBreaker.on('halfOpen', () => {
  console.info('Retell AI circuit HALF-OPEN - testing recovery');
});

retellaiBreaker.on('close', () => {
  console.info('Retell AI circuit CLOSED - normal operation');
});

// Usage
async function safeRetell AICall<T>(fn: () => Promise<T>): Promise<T> {
  return retellaiBreaker.fire(fn);
}

Idempotency Keys

Copyimport { v4 as uuidv4 } from 'uuid';
import crypto from 'crypto';

// Generate deterministic idempotency key from input
function generateIdempotencyKey(
  operation: string,
  params: Record<string, any>
): string {
  const data = JSON.stringify({ operation, params });
  return crypto.createHash('sha256').update(data).digest('hex');
}

// Or use random key with storage
class IdempotencyManager {
  private store: Map<string, { key: string; expiresAt: Date }> = new Map();

  getOrCreate(operationId: string): string {
    const existing = this.store.get(operationId);
    if (existing && existing.expiresAt > new Date()) {
      return existing.key;
    }

    const key = uuidv4();
    this.store.set(operationId, {
      key,
      expiresAt: new Date(Date.now() + 24 * 60 * 60 * 1000),
    });
    return key;
  }
}

Bulkhead Pattern

Copyimport PQueue from 'p-queue';

// Separate queues for different operations
const retellaiQueues = {
  critical: new PQueue({ concurrency: 10 }),
  normal: new PQueue({ concurrency: 5 }),
  bulk: new PQueue({ concurrency: 2 }),
};

async function prioritizedRetell AICall<T>(
  priority: 'critical' | 'normal' | 'bulk',
  fn: () => Promise<T>
): Promise<T> {
  return retellaiQueues[priority].add(fn);
}

// Usage
await prioritizedRetell AICall('critical', () =>
  retellaiClient.processPayment(order)
);

await prioritizedRetell AICall('bulk', () =>
  retellaiClient.syncCatalog(products)
);

Timeout Hierarchy

Copyconst TIMEOUT_CONFIG = {
  connect: 5000,      // Initial connection
  request: 30000,     // Standard requests
  upload: 120000,     // File uploads
  longPoll: 300000,   // Webhook long-polling
};

async function timedoutRetell AICall<T>(
  operation: 'connect' | 'request' | 'upload' | 'longPoll',
  fn: () => Promise<T>
): Promise<T> {
  const timeout = TIMEOUT_CONFIG[operation];

  return Promise.race([
    fn(),
    new Promise<never>((_, reject) =>
      setTimeout(() => reject(new Error(`Retell AI ${operation} timeout`)), timeout)
    ),
  ]);
}

Graceful Degradation

Copyinterface Retell AIFallback {
  enabled: boolean;
  data: any;
  staleness: 'fresh' | 'stale' | 'very_stale';
}

async function withRetell AIFallback<T>(
  fn: () => Promise<T>,
  fallbackFn: () => Promise<T>
): Promise<{ data: T; fallback: boolean }> {
  try {
    const data = await fn();
    // Update cache for future fallback
    await updateFallbackCache(data);
    return { data, fallback: false };
  } catch (error) {
    console.warn('Retell AI failed, using fallback:', error.message);
    const data = await fallbackFn();
    return { data, fallback: true };
  }
}

Dead Letter Queue

Copyinterface DeadLetterEntry {
  id: string;
  operation: string;
  payload: any;
  error: string;
  attempts: number;
  lastAttempt: Date;
}

class Retell AIDeadLetterQueue {
  private queue: DeadLetterEntry[] = [];

  add(entry: Omit<DeadLetterEntry, 'id' | 'lastAttempt'>): void {
    this.queue.push({
      ...entry,
      id: uuidv4(),
      lastAttempt: new Date(),
    });
  }

  async processOne(): Promise<boolean> {
    const entry = this.queue.shift();
    if (!entry) return false;

    try {
      await retellaiClient[entry.operation](entry.payload);
      console.log(`DLQ: Successfully reprocessed ${entry.id}`);
      return true;
    } catch (error) {
      entry.attempts++;
      entry.lastAttempt = new Date();

      if (entry.attempts < 5) {
        this.queue.push(entry);
      } else {
        console.error(`DLQ: Giving up on ${entry.id} after 5 attempts`);
        await alertOnPermanentFailure(entry);
      }
      return false;
    }
  }
}

Health Check with Degraded State

Copytype HealthStatus = 'healthy' | 'degraded' | 'unhealthy';

async function retellaiHealthCheck(): Promise<{
  status: HealthStatus;
  details: Record<string, any>;
}> {
  const checks = {
    api: await checkApiConnectivity(),
    circuitBreaker: retellaiBreaker.stats(),
    dlqSize: deadLetterQueue.size(),
  };

  const status: HealthStatus =
    !checks.api.connected ? 'unhealthy' :
    checks.circuitBreaker.state === 'open' ? 'degraded' :
    checks.dlqSize > 100 ? 'degraded' :
    'healthy';

  return { status, details: checks };
}

Instructions

Step 1: Implement Circuit Breaker

Wrap Retell AI calls with circuit breaker.

Step 2: Add Idempotency Keys

Generate deterministic keys for operations.

Step 3: Configure Bulkheads

Separate queues for different priorities.

Step 4: Set Up Dead Letter Queue

Handle permanent failures gracefully.

Output

• Circuit breaker protecting Retell AI calls
• Idempotency preventing duplicates
• Bulkhead isolation implemented
• DLQ for failed operations

Error Handling

Examples

Quick Circuit Check

Copyconst state = retellaiBreaker.stats().state;
console.log('Retell AI circuit:', state);

Resources

• Circuit Breaker Pattern
• Opossum Documentation
• Retell AI Reliability Guide

Next Steps

For policy enforcement, see retellai-policy-guardrails.