varunr89 /call -- Automated Phone Calls from Claude Code
Make phone calls that leave voicemails, navigate IVR menus, and warm-transfer live humans to your phone.
Invocation
/call <phone_number> <purpose in natural language>
Examples:
/call 3606765437 ask about enrollment for my 2.5yo daughter
/call 2065551234 schedule a dentist appointment for next week
/call 8005551234 cancel my internet service
How It Works
- You provide a phone number and purpose
- Claude Code generates a voicemail message and IVR navigation goal
- You confirm before the call is placed
- Azure OpenAI TTS HD pre-generates the voicemail audio
- Pipecat server starts and dials via Twilio
- Twilio's AMD detects human vs machine:
- Voicemail: plays pre-generated message, hangs up
- IVR Menu: Azure Whisper transcribes options, Claude decides which button to press
- Human answers: warm-transfers to your phone with a context whisper
- Call log saved to
call-logs/in current project
Architecture
Claude Code (brain, makes all decisions)
+ Pipecat Server (sandboxed voice worker, FastAPI + Twilio WebSocket)
+ Twilio (telephony, AMD, DTMF, call transfer)
+ Azure OpenAI gpt-4o-mini-transcribe (STT, segmented)
+ Azure OpenAI TTS HD (voicemail audio, pre-generated)
Security boundary: Pipecat is a sandboxed low-privilege process. It handles audio only. Claude Code never receives raw call audio -- only text transcripts. This prevents caller prompt injection from reaching Claude Code's privileged tools.
Call States
requested → dialing → ringing → answered
│
┌───────────┼───────────┐
▼ ▼ ▼
voicemail ivr_nav human
│ │ │
▼ ▼ ▼
leaving_msg navigating transferring
│ │ │
└───────────┼───────────┘
▼
completed
Terminal reasons: voicemail_left, transferred, no_answer, busy, ivr_failed, call_dropped, transfer_failed, timeout, error
Setup (First Time)
Run the setup script:
${CLAUDE_PLUGIN_ROOT}/scripts/setup.sh
This will:
- Create a Python venv and install dependencies (pipecat-ai, twilio, openai, fastapi)
- Prompt for Twilio account SID, auth token, and phone number
- Prompt for Azure OpenAI endpoint and API key
- Prompt for your phone number (for warm transfers)
- Prompt for ngrok auth token
- Save config to
${CLAUDE_PLUGIN_ROOT}/config.json
Required External Services
- Twilio account with a US phone number (~$1/mo + $0.014/min)
- Azure OpenAI endpoint with gpt-4o-mini-transcribe and TTS HD deployed
- ngrok account (free tier is sufficient)
Configuration
Config stored at ${CLAUDE_PLUGIN_ROOT}/config.json:
{
"twilio": {
"account_sid": "ACxxxxxxxx",
"auth_token": "xxxxx",
"from_number": "+1XXXXXXXXXX"
},
"azure_openai": {
"endpoint": "https://xxx.openai.azure.com",
"api_key": "xxxxx",
"tts_model": "tts-hd",
"tts_voice": "onyx",
"stt_model": "gpt-4o-mini-transcribe"
},
"transfer_to": "+16083207152",
"ngrok_auth_token": "xxxxx",
"pipecat_port": 8765
}
Call Log Format
Saved to <project>/call-logs/YYYY-MM-DD-xxxx<last4>.md:
# Call: (360) ***-5437
**Date:** 2026-03-22 2:34 PM
**Purpose:** Ask about enrollment for 2.5yo
**Outcome:** Voicemail left
**Duration:** 45 seconds
## Transcript
[0:00] IVR: "Thank you for calling..."
[0:08] Agent: Sent DTMF 1 (enrollment)
[0:15] Voicemail: "Please leave a message after the tone"
[0:18] Agent: Played voicemail message
Error Handling
- TTS fails: Falls back to Twilio
<Say>(robotic but works) - STT fails: Cannot navigate IVR. Leaves voicemail instead.
- Your phone doesn't answer transfer: Apologizes to center, hangs up
- IVR stuck (3 attempts): Leaves voicemail and hangs up
- Config missing: Shows setup instructions
Every call produces a log. No call ends silently.
Cost
~$0.03-0.05 per call (Twilio minutes + AMD + Azure OpenAI tokens).
Implementation
The skill logic is in $ARGUMENTS:
- Parse phone number (first token) and purpose (remaining text)
- Normalize number to E.164 format
- Read config from
${CLAUDE_PLUGIN_ROOT}/config.json - Generate voicemail message text from purpose
- Show confirmation prompt
- On confirm: generate TTS audio, start Pipecat server, orchestrate call
- Poll events, make IVR/transfer/voicemail decisions
- Write call log on completion