Voicemail detection

Overview

The Voicemail Detection tool allows your ElevenLabs agent to automatically identify when a call has been answered by a voicemail system rather than a human. This system tool enables agents to handle automated voicemail scenarios gracefully by either leaving a pre-configured message or ending the call immediately.

Functionality

• Automatic Detection: The LLM analyzes conversation patterns to identify voicemail systems based on automated greetings and prompts
• Configurable Response: Choose to either leave a custom voicemail message or end the call immediately when voicemail is detected
• Call Termination: After detection and optional message delivery, the call is automatically terminated
• Status Tracking: Voicemail detection events are logged and can be viewed in conversation history and batch call results

Parameters:

• reason (string, required): The reason for detecting voicemail (e.g., “automated greeting detected”, “no human response”)

Function call format:

{
  "type": "function",
  "function": {
    "name": "voicemail_detection",
    "arguments": "{\"reason\": \"Automated greeting detected with request to leave message\"}"
  }
}

Configuration Options

The voicemail detection tool can be configured with the following options:

• Voicemail Message: You can configure an optional custom message to be played when voicemail is detected. This message supports dynamic variables, allowing you to personalize voicemail messages with runtime values such as {{user_name}} or {{appointment_time}}

API Implementation

When creating an agent via API, you can add the Voicemail Detection tool to your agent configuration. It should be defined as a system tool:

from elevenlabs import AgentConfig, ConversationalConfig, ElevenLabs
elevenlabs = ElevenLabs(api_key="YOUR_API_KEY")
response = elevenlabs.conversational_ai.agents.create(
    conversation_config=ConversationalConfig(
        agent=AgentConfig(
            prompt={
                "built_in_tools": {
                    "voicemail_detection": {
                        "type": "system",
                        "name": "voicemail_detection",
                        # Optional: customize when the tool should be triggered
                        "description": "",
                        "params": {
                            "system_tool_type": "voicemail_detection",
                            # Optional: message left when voicemail is detected
                            "voicemail_message": "Sorry I missed you. I'll call back later.",
                        },
                    }
                }
            },
        ),
    ),
)