Retellai Hello World

---
name: retellai-hello-world
description: "\"Retell AI hello world \\u2014 AI voice agent and phone call automation.\\n\\ Use when working with Retell AI for voice agents, phone calls, or telephony.\\nTrigger\\ \\ with phrases like \\\"retell hello world\\\", \\\"retellai-hello-world\\\", \\\"voice agent\\\"\\ .\\n\""
allowed-tools: "Read, Write, Edit, Bash(npm:*), Bash(curl:*), Grep"
category: ai-agents-and-harness
source_repo: jeremylongshore/claude-code-plugins-plus-skills
source_path: "skills/.curated/retellai-hello-world/SKILL.md"
source_url: https://github.com/jeremylongshore/claude-code-plugins-plus-skills/blob/HEAD/skills/.curated/retellai-hello-world/SKILL.md
---

# 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

```typescript
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

```typescript
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

```typescript
// 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

```typescript
// 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

```typescript
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 testing |

## Resources

- [Retell AI Documentation](https://docs.retellai.com)
- [Create Phone Call](https://docs.retellai.com/api-references/create-phone-call)

## Next Steps

Configure agent behavior: `retellai-core-workflow-a`

---

**Source:** [`jeremylongshore/claude-code-plugins-plus-skills`](https://github.com/jeremylongshore/claude-code-plugins-plus-skills) → `skills/.curated/retellai-hello-world/SKILL.md`

**Also appears in:** `jeremylongshore/claude-code-plugins-plus-skills/plugins/saas-packs/retellai-pack/skills/retellai-hello-world/SKILL.md`