> ## Documentation Index
> Fetch the complete documentation index at: https://docs.getusertrace.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Retell AI Integration

> Test voice agents built with Retell AI platform

Test your Retell AI-powered voice agents by connecting them to UserTrace. Our simulated users will interact with your Retell agents through realistic voice conversations.

## Getting Started

### 1. Connect Your Retell Agent

In the UserTrace dashboard, navigate to **Agent Setup** and select **Retell AI Integration**.

**Required Information:**

* Retell Agent ID
* Retell API Key

**Example:**

```
Retell Agent ID: agent_1234567890abcdef
```

### 2. Set Evaluation Context

Define your pass and fail criteria for voice interactions:

**Example Pass/Fail Criteria:**

```
Pass Criteria:
- Natural conversation flow
- Quick response times (< 2 seconds)
- Accurate understanding of user requests
- Professional and friendly tone
- Successful task completion

Fail Criteria:
- Robotic or unnatural speech
- Long response delays (> 5 seconds)
- Misunderstanding simple requests
- Inappropriate tone or language
- Failing to complete requested tasks
```

## Testing Process

### Inbound Agent Testing

For Retell agents that handle incoming calls:

1. Our test number calls your Retell agent
2. Retell processes the conversation using your agent configuration
3. The conversation follows the defined scenario
4. Results are analyzed and scored

### Outbound Agent Testing

For Retell agents that make outgoing calls:

1. UserTrace triggers your Retell agent via API
2. Your agent calls our designated test number (5-minute window)
3. Our simulated user responds according to the scenario
4. The conversation continues until completion
5. Results are analyzed and scored

**Key Requirements:**

* **Call our number when simulation starts** (5-minute window)
* **Use the exact Retell agent** you configured in setup
* **Ensure your agent is deployed** and accessible

## Retell-Specific Features

### Voice Configuration

**Voice Models:**

* Test different Retell voice options
* Verify voice consistency across calls
* Check pronunciation and clarity

**Language Support:**

* Test multilingual capabilities
* Verify accent and dialect handling
* Check language switching functionality

### LLM Integration

**Custom Prompts:**

* Test your agent's custom system prompts
* Verify behavior consistency
* Check edge case handling

**Function Calling:**

* Test API integrations through voice commands
* Verify parameter extraction accuracy
* Ensure proper error handling

### Real-Time Features

**Interruption Handling:**

* Test natural conversation interruptions
* Verify smooth resumption of speech
* Check context preservation

**Live Transcription:**

* Monitor real-time transcription accuracy
* Test with various accents and speaking speeds
* Verify noise handling capabilities

## Best Practices

<CardGroup cols={2}>
  <Card title="Performance" icon="zap">
    **Response Optimization**

    • Target \< 2 second response times
    • Use Retell's streaming features
    • Optimize LLM prompt length
    • Monitor latency metrics
  </Card>

  <Card title="Conversation Design" icon="comments">
    **Natural Interactions**

    • Design clear conversation flows
    • Handle ambiguous inputs gracefully
    • Use appropriate filler words and pauses
    • Test various speaking styles
  </Card>
</CardGroup>

## Common Scenarios

**Customer Service:**

* Support ticket resolution
* Order status inquiries
* Account management
* Technical troubleshooting

**Sales & Marketing:**

* Lead qualification calls
* Product demonstrations
* Follow-up conversations
* Appointment setting

**Healthcare & Wellness:**

* Appointment scheduling
* Symptom assessment
* Medication reminders
* Health surveys

## Troubleshooting

**Common Issues:**

**Retell Agent Issues:**

* **Agent not responding**: Check agent deployment status in Retell dashboard
* **Poor voice quality**: Verify voice model settings and network connection
* **Function calls failing**: Validate API endpoints and authentication
* **Inconsistent responses**: Review and optimize system prompts

**Call Connectivity:**

* **Calls not connecting**: Ensure phone number is properly configured
* **Audio issues**: Check Retell's audio settings and network quality
* **Dropped calls**: Monitor Retell's connection stability
* **Latency problems**: Optimize LLM response generation

## Advanced Configuration

### Custom Integrations

**Webhook Configuration:**

```json theme={null}
{
  "webhook_url": "https://your-domain.com/retell-webhook",
  "events": ["call_started", "call_ended", "function_called"],
  "authentication": {
    "type": "bearer_token",
    "token": "your-webhook-secret"
  }
}
```

**API Integration Example:**

```javascript theme={null}
// Trigger outbound call via Retell API
const response = await fetch('https://api.retellai.com/call', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer ' + RETELL_API_KEY,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    agent_id: 'agent_1234567890abcdef',
    to_number: '+1-555-TEST-NUM',
    from_number: '+1-555-YOUR-NUM'
  })
});
```

<Note>
  **Need help with Retell AI setup?** Check the [Retell AI documentation](https://docs.retellai.com) or contact [support@getusertrace.com](mailto:support@getusertrace.com).
</Note>