Voice Integration

Voice Calls with Your AI Agent

OpenAI Realtime • LiveKit • WhatsApp Voice Notes • Assessment

Verdict

Should you build voice calls? Not now — low ROI for personal use
WhatsApp voice notes? Yes — covers 90% of the use case
Best voice call approach OpenAI Realtime SIP (if ever needed)
Cost per minute (voice call) ~$0.30/min (OpenAI Realtime) or ~$0.15/min (DIY pipeline)

1. Why Voice Is a Distraction (For Now)

Where Text (WhatsApp) Is Better

  • Precision — ticker symbols, numbers, parameters are more reliable in text
  • Audit trail — searchable, quotable, archivable
  • Async — respond when ready, not in real-time
  • Cost — 10-100x cheaper than voice API calls
  • Complexity — multi-step instructions are clearer in text
  • Charts/tables — voice cannot show you a chart

Where Voice Adds Value

  • Driving/walking — dictating trade ideas hands-free
  • Quick status checks — "What's my PnL today?"
  • Brainstorming — talking through a thesis is more natural
  • Emergency alerts — agent calls YOU when something breaks
Assessment: WhatsApp voice notes handle the "I want to talk to my agent" use case at near-zero cost and zero new infrastructure. The 10-second round-trip latency of a voice note is rarely a problem when you're the only user. Build phone calling only if you find yourself repeatedly wishing you could interrupt the agent mid-response.

2. Option Comparison

ApproachSetupMonthly FixedPer MinuteLLMBest For
WhatsApp Voice Notes 1-2 days $0 ~$0.05 Any (Claude) Daily async use
OpenAI Realtime SIP 1-2 days ~$1 (Twilio) ~$0.30 GPT only Real-time phone calls
LiveKit + Claude 3-5 days ~$1 + hosting ~$0.15-0.20 Any (Claude) Full control, Claude as brain
Vapi.ai 1 hour $0 ~$0.15-0.30 Any Fast prototype
ElevenLabs Agent 1-2 days $5-99 ~$0.10 Any Best voice quality

3. How Each Approach Works

A. WhatsApp Voice Notes (Recommended First Step)

NanoClaw already has a /add-voice-transcription skill that adds voice note processing. The flow:

Voice Note
WhatsApp
→
Whisper
OpenAI STT
→
Claude
processes text
→
Text Reply
WhatsApp

Cost: ~$0.003 per 30-second voice note (Whisper) + Claude API. No new infrastructure. Built-in NanoClaw skill.

B. OpenAI Realtime SIP (If Voice Calls Are Needed Later)

OpenAI added native SIP support, making phone-to-AI remarkably simple:[1]

Phone Call
any phone
→
Twilio SIP
~$1/mo + $0.014/min
→
OpenAI Realtime
native speech-to-speech
→
Response
voice output

The model supports function calling mid-conversation — it could check portfolio positions or trigger actions while you're talking. However, it's GPT only (no Claude).

Cost: ~$0.30/min with gpt-realtime, ~$0.11/min with gpt-realtime-mini. A 5-minute call runs $0.55-1.50.

C. LiveKit + Claude (If Claude Must Be the Brain)

Open-source WebRTC framework with Python SDK. Plug in any STT (Deepgram), LLM (Claude), and TTS (ElevenLabs). Self-hostable. Native Twilio SIP integration for phone calls.[2]

Most flexible but most setup work. Higher latency (~500-800ms) vs. OpenAI Realtime (~300-500ms) because it's a pipeline, not native speech-to-speech.

4. Recommended Priority

PriorityWhatEffortValue
1 WhatsApp voice notes — receive voice, transcribe, respond with text 1-2 days High (huge convenience gain)
2 Skip to other priorities (email, calendar, scheduled tasks) — Higher ROI than voice calls
3 Phone calling via SIP — only after months of WhatsApp use proves the need 1-2 days Low for personal use

Sources

  1. OpenAI Realtime SIP Integration — Official Docs
  2. LiveKit Voice AI Quickstart — LiveKit Docs
  3. OpenAI Realtime API Pricing — OpenAI
  4. Vapi.ai Pricing
  5. ElevenLabs Pricing