> For a complete page index, fetch https://docs.synthflow.ai/llms.txt. For full documentation content, fetch https://docs.synthflow.ai/llms-full.txt.

## Voicemail message configuration and `voicemail_message_left` end call reason

You can now configure your agent to leave a voicemail message when it detects voicemail, instead of hanging up. The new `voicemail_message` object on the assistant endpoints supports two modes:

| Field           | Description                                                                  |
| --------------- | ---------------------------------------------------------------------------- |
| `enabled`       | Whether voicemail message leaving is enabled                                 |
| `mode`          | `exact_message` (speak a fixed message) or `prompt` (generate from a prompt) |
| `exact_message` | The exact message to leave on the voicemail                                  |
| `prompt`        | A prompt used to generate the voicemail message                              |

When the agent successfully leaves a voicemail, the call status is `left_voicemail` and the end call reason is `voicemail_message_left`.

**Note:** Enabling `voicemail_message` requires `greeting_message_mode` to be set to `human`. Voicemail detection relies on the agent listening for the initial speaker to determine if it is a human or a voicemail machine.

**Updated endpoints:**

| Endpoint                                                                                | Title           |
| --------------------------------------------------------------------------------------- | --------------- |
| [**POST /assistants**](/api-reference/platform-api/agents/create-assistant)             | Create an agent |
| [**PUT /assistants/\{model\_id}**](/api-reference/platform-api/agents/update-assistant) | Update an agent |
| [**GET /assistants/\{model\_id}**](/api-reference/platform-api/agents/get-assistant)    | Get an agent    |

For more details, see the [Call Configuration](/call-configuration) documentation.