Complete Retell AI integration skill pack with 30 skills covering AI voice agents, phone automation, conversational AI, and call center solutions. Flagship+ tier vendor pack.

30 Skills

MIT License

Free Pricing

Installation

Open Claude Code and run this command:

/plugin install retellai-pack@claude-code-plugins-plus

Use --global to install for all projects, or --project for current project only.

Skills (30)

retellai-advanced-troubleshooting SKILL.md View full skill →

Retell AI advanced troubleshooting — AI voice agent and phone call automation.

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retellai-architecture-variants SKILL.md View full skill →

Retell AI architecture variants — AI voice agent and phone call automation.

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retellai-ci-integration SKILL.md View full skill →

Retell AI ci integration — AI voice agent and phone call automation.

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retellai-common-errors SKILL.md View full skill →

Diagnose and fix Retell AI voice agent errors: call failures, webhook issues, voice quality.

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Retell AI Common Errors

Overview

Quick reference for the top Retell AI errors and their solutions.

Prerequisites

retell-sdk installed
API key configured

Instructions

Error 1: 401 Unauthorized


RetellError: 401 — Invalid API key

Fix: Verify API key in Retell Dashboard. Ensure RETELLAPIKEY starts with key_.

Error 2: Call Fails Immediately


RetellError: 400 — Invalid phone number format

Fix: Use E.164 format: +14155551234. Both fromnumber and tonumber must be valid.

Error 3: Agent Not Responding


Call connected but agent says nothing

Fix: Check LLM configuration:


const llm = await retell.llm.retrieve(agent.response_engine.llm_id);
console.log(`Model: ${llm.model}`);
console.log(`Prompt length: ${llm.general_prompt.length} chars`);
// Ensure general_prompt is not empty and gives clear instructions

Error 4: Function Call Timeout


Function call to https://your-api.com/endpoint timed out

Fix: Your function endpoint must respond within 5 seconds. Offload heavy work:


app.post('/functions/lookup', async (req, res) => {
  // Respond immediately with acknowledgment
  const result = await quickLookup(req.body.args);
  res.json({ result: `Found: ${result.name}` });
  // Do NOT run async work before responding
});

Error 5: Webhook Not Receiving Events


No webhook events received after call

Fix: Set webhook_url on the agent, not just in Dashboard settings:


await retell.agent.update(agentId, {
  webhook_url: 'https://your-app.com/webhooks/retell',
});

Error 6: Voice Quality Issues


Agent voice sounds robotic/choppy

Fix: Check network latency to Retell servers. Use a voice optimized for your use case. Try different voice IDs.

Output

Error identified and root cause found
Fix applied and verified
Call successfully completed

Error Handling

HTTP Code	Meaning	Retryable
400	Bad request	No — fix params
401	Invalid API key	No — fix key
404	Agent/call not found	No — fix ID
429	Rate limited	Yes — backoff
500+	Server error	Yes — retry

Resources

retellai-core-workflow-a SKILL.md View full skill →

Retell AI core workflow a — AI voice agent and phone call automation.

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Retell AI Core Workflow A

Overview

Build and configure voice agents with custom prompts, function calling, and call flow logic.

Prerequisites

Completed retellai-hello-world

Instructions

Step 1: Agent with Function Calling


const llm = await retell.llm.create({
  model: 'gpt-4o',
  general_prompt: `You are a booking assistant for Dr. Smith's office.
    - Help callers book, reschedule, or cancel appointments
    - Collect: name, phone, preferred date/time
    - Confirm all details before booking`,
  functions: [
    {
      name: 'book_appointment',
      description: 'Book a new appointment',
      parameters: {
        type: 'object',
        properties: {
          patient_name: { type: 'string' },
          phone: { type: 'string' },
          date: { type: 'string', description: 'YYYY-MM-DD format' },
          time: { type: 'string', description: 'HH:MM format' },
        },
        required: ['patient_name', 'phone', 'date', 'time'],
      },
      url: 'https://your-api.com/appointments',
      speak_during_execution: true,
      speak_after_execution: true,
    },
  ],
});

Step 2: Configure Voice and Behavior


const agent = await retell.agent.create({
  response_engine: { type: 'retell-llm', llm_id: llm.llm_id },
  voice_id: '11labs-Rachel',
  agent_name: 'Dr. Smith Booking Agent',
  language: 'en-US',
  opt_out_sensitive_data_storage: false,
  end_call_after_silence_ms: 10000,  // End call after 10s silence
  max_call_duration_ms: 300000,       // 5-minute max
  enable_backchannel: true,           // "mhm", "yeah" responses
  boosted_keywords: ['appointment', 'schedule', 'Dr. Smith'],
});

Step 3: Update Agent Configuration


await retell.agent.update(agent.agent_id, {
  voice_id: '11labs-Dorothy',  // Change voice
  end_call_after_silence_ms: 15000,
});

Output

Agent with custom LLM prompt and function calling
Voice and behavior configuration
Real-time function execution during calls

Error Handling

Error	Cause	Solution
Function not triggering	Prompt doesn't guide to function	Include function use in prompt
Voice quality issues	Wrong voice selection	Test different voices
Call ending too early	Short silence timeout	Increase `endcallaftersilencems`

Resources

Retell A

retellai-core-workflow-b SKILL.md View full skill →

Retell AI core workflow b — AI voice agent and phone call automation.

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retellai-cost-tuning SKILL.md View full skill →

Retell AI cost tuning — AI voice agent and phone call automation.

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retellai-data-handling SKILL.md View full skill →

Retell AI data handling — AI voice agent and phone call automation.

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retellai-debug-bundle SKILL.md View full skill →

Retell AI debug bundle — AI voice agent and phone call automation.

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retellai-deploy-integration SKILL.md View full skill →

Retell AI deploy integration — AI voice agent and phone call automation.

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retellai-enterprise-rbac SKILL.md View full skill →

Retell AI enterprise rbac — AI voice agent and phone call automation.

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retellai-hello-world SKILL.md View full skill →

Retell AI hello world — AI voice agent and phone call automation.

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Retell AI Hello World

Overview

Create your first Retell AI voice agent and make a test phone call.

Prerequisites

Completed retellai-install-auth
A phone number registered in Retell AI Dashboard (or use web call for testing)

Instructions

Step 1: Create an LLM Configuration


import Retell from 'retell-sdk';
const retell = new Retell({ apiKey: process.env.RETELL_API_KEY! });

// Create LLM configuration (what the agent says)
const llm = await retell.llm.create({
  model: 'gpt-4o',
  general_prompt: `You are a friendly receptionist for Acme Corp.
    - Greet callers warmly
    - Ask how you can help
    - Take messages if needed
    - Be concise and professional`,
});
console.log(`LLM created: ${llm.llm_id}`);

Step 2: Create a Voice Agent


const agent = await retell.agent.create({
  response_engine: {
    type: 'retell-llm',
    llm_id: llm.llm_id,
  },
  voice_id: '11labs-Adrian',  // Choose from available voices
  agent_name: 'Acme Receptionist',
});
console.log(`Agent created: ${agent.agent_id}`);

Step 3: Make a Test Phone Call


// Outbound call (requires a registered phone number)
const call = await retell.call.createPhoneCall({
  from_number: '+14155551234',  // Your Retell number
  to_number: '+14155555678',    // Destination
  override_agent_id: agent.agent_id,
});
console.log(`Call initiated: ${call.call_id}`);

Step 4: Or Test with Web Call


// Web call (no phone number needed — great for testing)
const webCall = await retell.call.createWebCall({
  agent_id: agent.agent_id,
});
console.log(`Web call URL: ${webCall.call_id}`);
// Use retell-client-js-sdk to connect from browser

Step 5: Check Call Status


const callDetail = await retell.call.retrieve(call.call_id);
console.log(`Status: ${callDetail.call_status}`);
console.log(`Duration: ${callDetail.end_timestamp - callDetail.start_timestamp}ms`);
if (callDetail.transcript) {
  console.log(`Transcript: ${callDetail.transcript}`);
}

Output

LLM configuration with custom prompt
Voice agent with selected voice
Test call initiated (phone or web)
Call status and transcript retrieved

Error Handling

Error Cause Solution

422 Invalid voice_id Unknown voice List available voices in Dashboard

400 No phone number Number not registered Register number in Dashboard first

Call not connecting

Destination unreachable

Try web call for test

retellai-incident-runbook SKILL.md View full skill →

Retell AI incident runbook — AI voice agent and phone call automation.

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retellai-install-auth SKILL.md View full skill →

Retell AI install auth — AI voice agent and phone call automation.

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retellai-known-pitfalls SKILL.md View full skill →

Retell AI known pitfalls — AI voice agent and phone call automation.

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retellai-load-scale SKILL.md View full skill →

Retell AI load scale — AI voice agent and phone call automation.

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retellai-local-dev-loop SKILL.md View full skill →

Retell AI local dev loop — AI voice agent and phone call automation.

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retellai-migration-deep-dive SKILL.md View full skill →

Retell AI migration deep dive — AI voice agent and phone call automation.

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retellai-multi-env-setup SKILL.md View full skill →

Retell AI multi env setup — AI voice agent and phone call automation.

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retellai-observability SKILL.md View full skill →

Retell AI observability — AI voice agent and phone call automation.

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retellai-performance-tuning SKILL.md View full skill →

Retell AI performance tuning — AI voice agent and phone call automation.

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retellai-policy-guardrails SKILL.md View full skill →

Retell AI policy guardrails — AI voice agent and phone call automation.

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retellai-prod-checklist SKILL.md View full skill →

Retell AI prod checklist — AI voice agent and phone call automation.

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retellai-rate-limits SKILL.md View full skill →

Retell AI rate limits — AI voice agent and phone call automation.

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retellai-reference-architecture SKILL.md View full skill →

Retell AI reference architecture — AI voice agent and phone call automation.

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retellai-reliability-patterns SKILL.md View full skill →

Retell AI reliability patterns — AI voice agent and phone call automation.

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retellai-sdk-patterns SKILL.md View full skill →

Production-ready Retell AI SDK patterns for voice agent applications.

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Retell AI SDK Patterns

Overview

Production-ready patterns for Retell AI: client singletons, typed agent configurations, call management, and error handling.

Prerequisites

Completed retellai-install-auth
retell-sdk installed

Instructions

Step 1: Singleton Client


import Retell from 'retell-sdk';

let _retell: Retell | null = null;

export function getRetellClient(): Retell {
  if (!_retell) {
    _retell = new Retell({ apiKey: process.env.RETELL_API_KEY! });
  }
  return _retell;
}

Step 2: Typed Agent Configuration


interface AgentConfig {
  name: string;
  voiceId: string;
  prompt: string;
  functions?: FunctionConfig[];
  maxCallDurationMs?: number;
  endCallAfterSilenceMs?: number;
}

async function createAgent(config: AgentConfig) {
  const retell = getRetellClient();

  const llm = await retell.llm.create({
    model: 'gpt-4o',
    general_prompt: config.prompt,
    functions: config.functions,
  });

  const agent = await retell.agent.create({
    response_engine: { type: 'retell-llm', llm_id: llm.llm_id },
    voice_id: config.voiceId,
    agent_name: config.name,
    max_call_duration_ms: config.maxCallDurationMs || 300000,
    end_call_after_silence_ms: config.endCallAfterSilenceMs || 10000,
  });

  return { agentId: agent.agent_id, llmId: llm.llm_id };
}

Step 3: Call Manager with Retry


async function makeCallWithRetry(
  fromNumber: string, toNumber: string, agentId: string, maxRetries = 2
) {
  const retell = getRetellClient();
  for (let attempt = 0; attempt <= maxRetries; attempt++) {
    try {
      const call = await retell.call.createPhoneCall({
        from_number: fromNumber,
        to_number: toNumber,
        override_agent_id: agentId,
      });
      return call;
    } catch (err: any) {
      if (attempt === maxRetries || err.status < 500) throw err;
      await new Promise(r => setTimeout(r, 2000 * (attempt + 1)));
    }
  }
}

Step 4: Batch Call Campaign


async function runCallCampaign(
  numbers: string[], agentId: string, concurrency = 3, delayMs = 2000
) {
  const results: Array<{ number: string; callId?: string; error?: string }> = [];
  const queue = [...numbers];
  const active = new Set<Promise<void>>();

  while (queue.length > 0 || active.size > 0) {
    while (active.size < concurrency && queue.length > 0) {
      const number = queue.shift()!;
      const p = (async () => {
        try {
          const call = await makeCallWithRetry(process.env.RETELL_PHONE_NUMBER!, number, agentId);
          results.push({ number, callId: call.call_id });
        } catch (err: any) {
          results.push({ number, error: err.message });


                
                  
                  
                  retellai-security-basics
                  SKILL.md
                  View full skill →
                
                
                  Retell AI security basics — AI voice agent and phone call automation.
                  
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                  Retell AI Security Basics
Overview
Implementation patterns for Retell AI security basics — voice agent and telephony platform.
Prerequisites

Completed retellai-install-auth setup

Instructions
Step 1: SDK Pattern

import Retell from 'retell-sdk';
const retell = new Retell({ apiKey: process.env.RETELL_API_KEY! });

const agents = await retell.agent.list();
console.log(`Agents: ${agents.length}`);

Output

Retell AI integration for security basics

Error Handling

Error
Cause
Solution


401 Unauthorized
Invalid API key
Check RETELLAPIKEY


429 Rate Limited
Too many requests
Implement backoff


400 Bad Request
Invalid parameters
Check API documentation


Resources

Retell AI Documentation
retell-sdk npm

Next Steps
See related Retell AI skills for more workflows.


                
                  
                  
                  retellai-upgrade-migration
                  SKILL.md
                  View full skill →
                
                
                  Retell AI upgrade migration — AI voice agent and phone call automation.
                  
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                  Retell AI Upgrade Migration
Overview
Implementation patterns for Retell AI upgrade migration — voice agent and telephony platform.
Prerequisites

Completed retellai-install-auth setup

Instructions
Step 1: SDK Pattern

import Retell from 'retell-sdk';
const retell = new Retell({ apiKey: process.env.RETELL_API_KEY! });

const agents = await retell.agent.list();
console.log(`Agents: ${agents.length}`);

Output

Retell AI integration for upgrade migration

Error Handling

Error
Cause
Solution


401 Unauthorized
Invalid API key
Check RETELLAPIKEY


429 Rate Limited
Too many requests
Implement backoff


400 Bad Request
Invalid parameters
Check API documentation


Resources

Retell AI Documentation
retell-sdk npm

Next Steps
See related Retell AI skills for more workflows.


                
                  
                  
                  retellai-webhooks-events
                  SKILL.md
                  View full skill →
                
                
                  Retell AI webhooks events — AI voice agent and phone call automation.
                  
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                  Retell AI Webhooks Events
Overview
Handle Retell AI webhook events for call lifecycle, transcripts, and function execution.
Prerequisites

HTTPS webhook endpoint
Agent configured with webhook URL

Instructions
Step 1: Configure Webhook URL

// Set webhook URL in agent configuration
await retell.agent.update(agentId, {
  webhook_url: 'https://your-app.com/webhooks/retell',
});

Step 2: Webhook Endpoint

import express from 'express';

const app = express();
app.post('/webhooks/retell', express.json(), async (req, res) => {
  const { event, call } = req.body;

  switch (event) {
    case 'call_started':
      console.log(`Call started: ${call.call_id} from ${call.from_number}`);
      break;

    case 'call_ended':
      console.log(`Call ended: ${call.call_id}`);
      console.log(`  Duration: ${call.duration_ms}ms`);
      console.log(`  Status: ${call.call_status}`);
      if (call.transcript) {
        await saveTranscript(call.call_id, call.transcript);
      }
      break;

    case 'call_analyzed':
      console.log(`Analysis ready: ${call.call_id}`);
      console.log(`  Summary: ${call.call_analysis?.call_summary}`);
      break;

    default:
      console.log(`Unhandled event: ${event}`);
  }

  res.status(200).json({ received: true });
});

Step 3: Handle Function Calls During Conversation

// When agent triggers a function, Retell calls your URL
app.post('/functions/book-appointment', express.json(), async (req, res) => {
  const { patient_name, phone, date, time } = req.body.args;

  // Process the booking
  const booking = await bookAppointment(patient_name, phone, date, time);

  // Return response for agent to speak
  res.json({
    result: `Appointment booked for ${patient_name} on ${date} at ${time}. Confirmation number: ${booking.id}`,
  });
});

Output

Webhook handling for call lifecycle events
Transcript storage on call completion
Function execution during live calls

Error Handling

Issue
Cause
Solution


No webhook events
URL not configured
Set webhook_url on agent


Function timeout
Slow backend
Respond within 5 seconds


Missing transcript
Short call
Transcript only for calls > 5 seconds


Resources

Retell AI Documentation
retell-sdk npm

Next Steps
Common errors: retellai-common-errors


          
        

      
      

      
      

      
      

      
      
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                Tons of Skills by Intent Solutions. Marine. Citadel Grad. 20 years ops → self-taught dev → AI architect.
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Error	Cause	Solution
Call fails immediately	Bad phone number format	Use E.164 format
No recording	Recording not enabled	Enable in agent settings
Concurrent limit	Too many active calls	Upgrade plan or queue calls

Error	Cause	Solution
401 Unauthorized	Invalid API key	Check RETELLAPIKEY
429 Rate Limited	Too many requests	Implement backoff
400 Bad Request	Invalid parameters	Check API documentation

retellai-pack

Installation

Skills (30)

Retell AI Advanced Troubleshooting

Overview

Prerequisites

Instructions

Step 1: SDK Pattern

Output

Error Handling

Resources

Next Steps

Retell AI Architecture Variants

Overview

Prerequisites

Instructions

Step 1: SDK Pattern

Output

Error Handling

Resources

Next Steps

Retell AI Ci Integration

Overview

Prerequisites

Instructions

Step 1: SDK Pattern

Output

Error Handling

Resources

Next Steps

Retell AI Common Errors

Overview

Prerequisites

Instructions

Error 1: 401 Unauthorized

Error 2: Call Fails Immediately

Error 3: Agent Not Responding

Error 4: Function Call Timeout

Error 5: Webhook Not Receiving Events

Error 6: Voice Quality Issues

Output

Error Handling

Resources

Retell AI Core Workflow A

Overview

Prerequisites

Instructions

Step 1: Agent with Function Calling

Step 2: Configure Voice and Behavior

Step 3: Update Agent Configuration

Output

Error Handling

Resources

Retell AI Core Workflow B

Overview

Prerequisites

Instructions

Step 1: Outbound Call Campaign

Step 2: List and Filter Calls

Step 3: Get Call Recording and Transcript

Output

Error Handling

Resources

Next Steps

Retell AI Cost Tuning

Overview

Prerequisites

Instructions

Step 1: SDK Pattern

Output

Error Handling

Resources

Next Steps

Retell AI Data Handling

Overview

Prerequisites

Instructions

Step 1: SDK Pattern

Output

Error Handling