Elevenlabs Voice Agent

Build and manage ElevenLabs Conversational AI voice agents with Twilio phone integration. Use when creating AI phone agents (cold callers, appointment setters, customer service), configuring voice/LLM settings, connecting Twilio phone numbers, or debugging voice agent issues. Covers NEPQ sales framework, objection handling, and call qualification flows.

Build AI phone agents using ElevenLabs Conversational AI API + Twilio.

Setup Flow

1. Create agent via ElevenLabs dashboard or API
2. Configure voice, TTS model, LLM, and system prompt
3. Purchase/connect Twilio phone number via ElevenLabs phone integration
4. Test and iterate on script, voice settings, turn-taking

Optimal Voice Settings (Proven)

Setting	Value	Why
TTS Model	v3 conversational	Best quality for phone calls
Expressive mode	ON	Natural inflection
Stability	0.45	Natural variation without inconsistency
Similarity	0.75	Recognizable voice
Speed	1.2x	Fast enough for cold calls (API max)
Streaming latency	4	Balance speed vs quality
Turn timeout	2s	Don't wait too long for response
Eagerness	eager	Jump in naturally
Speculative turn	ON	Faster responses
Cascade timeout	3s	Handle pauses

Recommended Voices

• Alexandra (kdmDKE6EkgrWrrykO9Qt): Pleasant female, great for cold calls
• Hope (OYTbf65OHHFELVut7v2H): Warm female backup

LLM Choice

Use gpt-4o-mini for phone agents — speed is critical, latency kills calls.

Key API Endpoints

text

POST https://api.elevenlabs.io/v1/convai/agents/create
PATCH https://api.elevenlabs.io/v1/convai/agents/{agent_id}
GET https://api.elevenlabs.io/v1/convai/agents/{agent_id}
POST https://api.elevenlabs.io/v1/convai/twilio/phone-numbers — Connect Twilio number

Enable Phone Features

Enable these tools on the agent: voicemail_detection, end_call, background_voice_detection

NEPQ Sales Framework

For appointment-setting agents, use Neuro-Emotional Persuasion Questioning:

• Permission-based opening ("Do you have a quick moment?")
• Question-led qualification (don't pitch, ask)
• Emotional connection questions before booking
• Soft close with specific time options

Twilio Integration

1. Get Twilio Account SID + Auth Token
2. Use ElevenLabs API to create phone number connection
3. Phone number is provisioned automatically by ElevenLabs
4. Calls route: Twilio → ElevenLabs → AI agent

Common Issues

• Robotic voice: Switch to v3 conversational model, enable expressive mode
• Slow responses: Use gpt-4o-mini, increase streaming latency optimization
• Cuts off caller: Increase turn timeout, reduce eagerness
• Sounds scripted: Add personality to system prompt, lower stability slightly