# Answer a call

Route incoming calls on a number to an agent.

:::steps
### Prepare

State what the reader needs before starting.

### Build

```ts
// The complete, runnable code for this guide goes here.
```

### Check the result

Show what success looks like, in the dashboard or in the output.
:::

## Troubleshooting

| Symptom            | Fix                                              |
| ------------------ | ------------------------------------------------ |
| `401 Unauthorized` | Check that `ELIOS_API_KEY` is set in this shell. |