voicemail_detection

Voicemail Detection Assistant

An outbound calling assistant that detects voicemail systems and handles live contacts appropriately.

Overview

This assistant monitors uses transcriptions to distinguish between voicemail systems and live humans. When voicemail is detected, it uses the leave_voicemail tool to deliver a pre-recorded message. For live contacts, it delivers a brief message and handles responses professionally.

How It Works

1. Voicemail Detection — The assistant uses transcriptions to detect common voicemail phrases (e.g., "Please leave a message after the beep", "Your call has been forwarded to voicemail") and triggers the leave_voicemail tool when confident.

2. Live Person Handling — When a human answers, the assistant delivers the message and responds to acknowledgments or questions briefly before ending the call.

3. Tool-Based Voicemail — Uses Vapi's voicemail tool type to deliver messages, ensuring the voicemail is left cleanly without the assistant speaking it aloud.

Project Contents

• assistant.json — Full assistant configuration with voicemail detection logic in the system prompt
• tools/leave_voicemail.json — Voicemail tool definition with trigger phrases and the message to leave

Key Configuration

Setting	Value
firstMessageMode	assistant-waits-for-user
voicemailDetectionEnabled	false
voicemailMessage	""

Documentation

• Voicemail Detection Tool

Notes

• This assistant uses prompt-based voicemail detection rather than Vapi's built-in voicemailDetectionEnabled flag
• Update the leave_voicemail tool's beepDetectionEnabled to true if you also want to detect voicemail based on beeps.
• Customize the voicemail message in tools/leave_voicemail.json under messages[0].content