Better Call Claude

Bi-directional communication for Claude Code via Voice Calls, SMS, and WhatsApp.
Call Claude from your phone to start tasks, and receive callbacks when Claude needs input or wants to share status.

📞 "Hey Claude, refactor the auth module and call me when you're done or need a decision."

[20 minutes later, phone rings]

🤖 "I've finished the refactor but found a security issue. Should I fix it now or create a ticket?"

💬 Or via SMS/WhatsApp:

You: "Claude, how's the deployment going?"

Claude: "Deployment complete. 3 services updated, all health checks passing."

Features

• 📱 Inbound calls - Call Claude Code from your phone to start tasks
• 📲 Outbound calls - Claude calls you when done, stuck, or needs decisions
• 💬 SMS messaging - Send and receive text messages with Claude
• 📱 WhatsApp - Full WhatsApp Business integration
• 🔄 Cross-channel context - Start on voice, continue on WhatsApp seamlessly
• 🔗 Persistent sessions - Claude stays alive listening for WhatsApp messages
• 🔒 Secure transports - Choose ngrok (easy) or Tailscale (enterprise-grade)
• 🗣️ Natural conversations - Multi-turn interactions across all channels
• 🔧 Tool composable - Claude can use other tools while communicating
• ⚡ Auto-webhook updates - Twilio webhooks auto-update when ngrok URL changes
• ⌚ Works anywhere - Phone, smartwatch, or any device

⚠️ Testing Status

Channel	Provider	Status
Voice	Twilio	✅ Tested & Working
WhatsApp	Twilio Sandbox	✅ Tested & Working
SMS	Twilio	⏳ Pending A2P 10DLC verification
Voice	Telnyx	🔬 Not yet tested
SMS	Telnyx	🔬 Not yet tested
WhatsApp	Telnyx	🔬 Not yet tested

Contributions welcome for testing other provider/channel combinations!

---

Quick Start

1. Get Required Accounts

Service	Purpose	Cost
Telnyx or Twilio	Phone calls	~$1/mo + usage
OpenAI	Speech-to-text & text-to-speech	~$0.03/min
ngrok OR Tailscale	Webhook tunneling	Free tier available

2. Set Up Phone Provider

Option A: Telnyx (Recommended - 50% cheaper)

1. Create account at portal.telnyx.com and verify identity
2. Buy a phone number (~$1/month)
3. Create a Voice API application:
   • Set webhook URL to your tunnel URL + /webhook/telnyx/inbound
   • Set API version to v2
4. Enable SMS on your phone number:
   • Go to Messaging and create a Messaging Profile
   • Assign your phone number to the profile
   • Set SMS webhook URL to your tunnel URL + /webhook/telnyx/sms
5. Enable WhatsApp (optional):
   • Go to WhatsApp in portal
   • Complete WhatsApp Business verification
   • Set webhook URL to your tunnel URL + /webhook/telnyx/whatsapp
6. Verify your phone number for outbound calls
7. Get your Connection ID (or Messaging Profile ID) and API Key

Option B: Twilio

1. Create account at twilio.com/console
2. Buy a phone number
3. Configure webhooks for your number:
   • Voice webhook: your tunnel URL + /webhook/twilio/inbound
   • SMS webhook: your tunnel URL + /webhook/twilio/sms
4. Enable WhatsApp (optional):
   • Go to WhatsApp Senders
   • Complete WhatsApp Business setup
   • Set webhook URL to your tunnel URL + /webhook/twilio/whatsapp
5. Get your Account SID and Auth Token

3. Choose Your Transport

Option A: ngrok (Recommended for beginners)

Pros: Instant setup, works everywhere, no network configuration

1. Sign up at ngrok.com
2. Copy your auth token from the dashboard
3. Set BETTERCALLCLAUDE_TRANSPORT=ngrok in your config

Option B: Tailscale (Recommended for enterprise/security)

Pros: No public URLs, works behind firewalls, stable addresses, enterprise-grade security

Requirements: Tailscale installed on both your computer AND your phone provider must support private webhooks (or use Tailscale Funnel)

1. Install Tailscale on your machine
2. Enable Tailscale Funnel for public webhook access:

   tailscale funnel 3333
   

3. Or use a relay server on your Tailscale network

4. Install Better Call Claude

# Quick start with bunx (recommended)
bunx better-call-claude

# Or install globally
bun install -g better-call-claude
better-call-claude

5. Add to Claude Code

Add to ~/.claude/settings.json:

{
  "mcpServers": {
    "better-call-claude": {
      "command": "bunx",
      "args": ["better-call-claude"],
      "env": {
        "BETTERCALLCLAUDE_PHONE_PROVIDER": "telnyx",
        "BETTERCALLCLAUDE_PHONE_ACCOUNT_SID": "your-connection-id",
        "BETTERCALLCLAUDE_PHONE_AUTH_TOKEN": "your-api-key",
        "BETTERCALLCLAUDE_PHONE_NUMBER": "+15551234567",
        "BETTERCALLCLAUDE_USER_PHONE_NUMBER": "+15559876543",
        "BETTERCALLCLAUDE_OPENAI_API_KEY": "sk-...",
        "BETTERCALLCLAUDE_TRANSPORT": "ngrok",
        "BETTERCALLCLAUDE_NGROK_AUTHTOKEN": "your-ngrok-token"
      }
    }
  }
}

Restart Claude Code. Done!

---

Environment Variables

Required Variables

Variable	Description
BETTERCALLCLAUDE_PHONE_PROVIDER	telnyx or twilio
BETTERCALLCLAUDE_PHONE_ACCOUNT_SID	Provider account/connection ID
BETTERCALLCLAUDE_PHONE_AUTH_TOKEN	Provider API key/auth token
BETTERCALLCLAUDE_PHONE_NUMBER	Your Telnyx/Twilio phone number (E.164)
BETTERCALLCLAUDE_WHATSAPP_NUMBER	WhatsApp number if different (e.g., Twilio Sandbox)
BETTERCALLCLAUDE_USER_PHONE_NUMBER	Your personal phone number
BETTERCALLCLAUDE_OPENAI_API_KEY	OpenAI API key for TTS/STT
BETTERCALLCLAUDE_TRANSPORT	ngrok or tailscale

Transport-Specific Variables

For ngrok:

Variable	Default	Description
BETTERCALLCLAUDE_NGROK_AUTHTOKEN	-	ngrok auth token (required)
BETTERCALLCLAUDE_NGROK_DOMAIN	-	Custom domain (paid feature)

For Tailscale:

Variable	Default	Description
BETTERCALLCLAUDE_TAILSCALE_HOSTNAME	auto	Your Tailscale hostname
BETTERCALLCLAUDE_TAILSCALE_USE_FUNNEL	false	Use Tailscale Funnel for public access
BETTERCALLCLAUDE_TAILSCALE_FUNNEL_PORT	443	Funnel port

Optional Variables

Variable	Default	Description
BETTERCALLCLAUDE_TTS_VOICE	onyx	OpenAI voice (alloy, echo, fable, onyx, nova, shimmer)
BETTERCALLCLAUDE_PORT	3333	Local HTTP server port
BETTERCALLCLAUDE_TRANSCRIPT_TIMEOUT_MS	180000	Speech timeout (3 min)
BETTERCALLCLAUDE_STT_SILENCE_DURATION_MS	800	End-of-speech detection

---

Usage

Voice Calls

You → Claude (Inbound Calls)

Call your Telnyx/Twilio phone number from your personal phone:

📱 "Hey Claude, I need you to write unit tests for the payment module. Call me when you're done."

Claude will acknowledge and start working. When done, it calls you back.

Claude → You (Outbound Calls)

Claude can initiate calls when it needs your input:

🤖 "I found 3 different approaches for the caching layer. Want me to explain them so you can choose?"

Voice Commands During Calls

• "Hang up" or "Goodbye" - End the call
• "Hold on" - Claude waits for you to continue
• "Go ahead" - Claude continues with the task
• "Cancel that" - Abort current action

---

SMS Messaging

You → Claude (Inbound SMS)

Text your Telnyx/Twilio number:

💬 "Hey Claude, what's the status of the deployment?"

Claude will respond via SMS:

🤖 "Deployment is 80% complete. Running integration tests now. ETA: 5 minutes."

Claude → You (Outbound SMS)

Claude can send you text updates:

🤖 "Build failed on line 42 of auth.ts. Reply with 'fix' to auto-fix or 'skip' to continue."

---

WhatsApp

You → Claude (Inbound WhatsApp)

Send a WhatsApp message to your business number:

💬 "Show me the error logs from the last hour"

Claude responds in WhatsApp:

🤖 "Found 3 errors:\n1. Connection timeout at 14:32\n2. Auth failure at 14:45\n3. Rate limit at 15:01\n\nWant me to investigate any of these?"

Claude → You (Outbound WhatsApp)

Claude can send rich WhatsApp messages:

🤖 "Code review complete! Found 2 issues:\n• Line 23: Unused variable\n• Line 67: Missing error handling\n\nReply 'fix' to auto-fix or 'details' for more info."

---

Cross-Channel Context

Start a task on voice and seamlessly continue on WhatsApp - Claude remembers everything.

Example Flow

1. Call Claude:

   📞 "Hey Claude, run the todo app in dev mode and let's continue on WhatsApp"

2. Claude starts the app and enters WhatsApp listening mode:

   🤖 "Todo app running on port 5173. Send me WhatsApp messages for more instructions."

3. Send WhatsApp message:

   💬 "Expose it via localtunnel and add the URL to allowed hosts"

4. Claude responds via WhatsApp:

   🤖 "Done! Localtunnel URL: https://xyz.loca.lt - I've added it to vite.config.ts allowedHosts"

5. Continue the conversation:

   💬 "What's the public IP so I can access it remotely?"

   🤖 "Your public IP is 203.0.113.42. Access the app at https://xyz.loca.lt"

Key phrases to trigger WhatsApp listening:

• "Continue on WhatsApp"
• "Let's talk on WhatsApp"
• "Listen for my WhatsApp messages"

---

WhatsApp Sandbox (Twilio)

For testing, you can use Twilio's WhatsApp Sandbox instead of a full WhatsApp Business account.

1. Go to Twilio Console > Messaging > WhatsApp Sandbox
2. Send the join code to the sandbox number (+1 415 523 8886)
3. Set the webhook URL to {your-ngrok-url}/webhook/twilio/whatsapp
4. Add to your config:

   "BETTERCALLCLAUDE_WHATSAPP_NUMBER": "+14155238886"
   

Note: Sandbox requires re-joining every 72 hours.

---

How It Works

┌─────────────────┐         ┌──────────────────────────────────┐
│   Your Phone    │────────>│      Phone Provider              │
│  📞 Voice       │<────────│   (Telnyx/Twilio)                │
│  💬 SMS         │         │                                  │
│  📱 WhatsApp    │         │   • Voice API                    │
└─────────────────┘         │   • Messaging API                │
                            │   • WhatsApp Business API        │
                            └──────────────┬───────────────────┘
                                           │ webhooks
                                           ▼
                            ┌──────────────────────────────────┐
                            │     Transport Layer              │
                            │  (ngrok / Tailscale Funnel)      │
                            └──────────────┬───────────────────┘
                                           │
                                           ▼
┌─────────────────┐         ┌──────────────────────────────────┐
│   Claude Code   │◄──────► │   Better Call Claude MCP Server  │
│   (your IDE)    │  stdio  │   (local, port 3333)             │
└─────────────────┘         │                                  │
                            │   • Voice handling               │
                            │   • SMS handling                 │
                            │   • WhatsApp handling            │
                            │   • Conversation management      │
                            └──────────────┬───────────────────┘
                                           │
                                           ▼
                            ┌──────────────────────────────────┐
                            │         OpenAI API               │
                            │    (Whisper STT + TTS)           │
                            │    (Voice calls only)            │
                            └──────────────────────────────────┘

Communication Flows

Voice:

1. Inbound: You call → Provider → Webhook → MCP Server → Claude Code
2. Outbound: Claude Code → MCP Server → Provider → Your phone rings
3. Speech: Your voice → Whisper STT → Text → Claude → TTS → Audio playback

SMS:

1. Inbound: You text → Provider → Webhook → MCP Server → Claude Code
2. Outbound: Claude Code → MCP Server → Provider API → SMS delivered

WhatsApp:

1. Inbound: You message → Provider → Webhook → MCP Server → Claude Code
2. Outbound: Claude Code → MCP Server → Provider API → WhatsApp delivered

---

MCP Tools

Voice Tools

receive_inbound_call

Accept and process an incoming call from the user.

initiate_call

Start a phone call to the user.

const { callId, response } = await initiate_call({
  message: "Hey! I finished the refactor. What should I work on next?"
});

continue_call

Continue an active call with follow-up messages.

const response = await continue_call({
  call_id: callId,
  message: "Got it. Should I also add the caching layer?"
});

speak_to_user

Speak without waiting for a response (for acknowledgments).

await speak_to_user({
  call_id: callId,
  message: "Let me search for that. One moment..."
});

end_call

End an active call.

await end_call({
  call_id: callId,
  message: "Perfect, I'll get started. Talk soon!"
});

get_call_status

Check status of current or recent calls.

const status = await get_call_status({ call_id: callId });
// { state: "active", duration: 45, transcript: [...] }

---

Messaging Tools

receive_inbound_message

Check for incoming SMS or WhatsApp messages.

const result = await receive_inbound_message({
  channel: "any",      // "sms", "whatsapp", or "any"
  timeout_ms: 5000     // How long to wait
});
// { success: true, channel: "sms", conversation_id: "...", message: "Deploy now" }

send_sms

Send an SMS message to the user.

const result = await send_sms({
  message: "Build complete! 42 tests passed.",
  wait_for_reply: true,
  timeout_ms: 180000
});
// { success: true, conversation_id: "...", reply: "Great, deploy it" }

send_whatsapp

Send a WhatsApp message to the user.

const result = await send_whatsapp({
  message: "Found 3 issues in code review:\n• Issue 1\n• Issue 2\n• Issue 3",
  wait_for_reply: true
});
// { success: true, conversation_id: "...", reply: "Fix issue 1 first" }

reply_to_conversation

Reply to an existing conversation (works for voice, SMS, or WhatsApp).

const result = await reply_to_conversation({
  conversation_id: "abc-123",
  message: "Got it, fixing issue 1 now.",
  wait_for_reply: false
});

get_conversation_history

Get the full message history for any conversation.

const history = await get_conversation_history({
  conversation_id: "abc-123"
});
// { success: true, channel: "whatsapp", messages: [...], state: "active" }

---

Costs

Voice Calls

Service	Cost
Telnyx outbound calls	~$0.007/min
Twilio outbound calls	~$0.014/min
OpenAI Whisper (STT)	~$0.006/min
OpenAI TTS	~$0.015/1K chars

Typical voice conversation: ~$0.03-0.05/minute

SMS

Service	Cost
Telnyx SMS (US)	~$0.004/message
Twilio SMS (US)	~$0.0079/message

Typical SMS exchange: ~$0.01-0.02/exchange

WhatsApp

Service	Cost
Telnyx WhatsApp	~$0.005/message
Twilio WhatsApp	~$0.005/message + conversation fees

Typical WhatsApp exchange: ~$0.01-0.02/exchange

Infrastructure

Service	Cost
Phone number	~$1/month
ngrok	Free tier available
Tailscale	Free for personal use

---

Security Considerations

With ngrok

• Public URLs can be discovered (use custom domains for production)
• Webhook signatures verified by default
• Consider IP allowlisting in ngrok dashboard

With Tailscale

• No public exposure by default
• Funnel creates public endpoint but traffic routes through Tailscale
• Integrates with SSO/SCIM for enterprise
• Audit logs available

General

• Phone numbers are never logged
• Call transcripts are ephemeral (cleared on restart)
• Use environment variables, never hardcode credentials

---

Troubleshooting

Voice Issues

Claude doesn't answer calls

1. Check the MCP server is running: claude --debug
2. Verify webhook URL is configured in provider dashboard
3. Ensure transport (ngrok/Tailscale) is active

Can't make outbound calls

1. Verify BETTERCALLCLAUDE_USER_PHONE_NUMBER is correct
2. Check phone number is verified with provider
3. Ensure sufficient balance in provider account

Audio quality issues

1. Check network connectivity
2. Try different TTS voice: BETTERCALLCLAUDE_TTS_VOICE=nova
3. Adjust silence detection: BETTERCALLCLAUDE_STT_SILENCE_DURATION_MS=1000

SMS Issues

SMS not being received

1. Verify SMS is enabled on your phone number in provider dashboard
2. Check SMS webhook URL is set: /webhook/telnyx/sms or /webhook/twilio/sms
3. Verify Messaging Profile is assigned to phone number (Telnyx)

Can't send outbound SMS

1. Check phone number has SMS capability
2. Verify destination number format (E.164: +15551234567)
3. Check provider account balance

WhatsApp Issues

WhatsApp messages not received

1. Verify WhatsApp Business is set up in provider portal
2. Check webhook URL: /webhook/telnyx/whatsapp or /webhook/twilio/whatsapp
3. Ensure WhatsApp Business verification is complete

Can't send WhatsApp messages

1. User must have messaged you first (WhatsApp 24-hour rule)
2. Check WhatsApp Business approval status
3. Verify message template compliance (for outbound-first messages)

Transport Issues

Tailscale Funnel not working

1. Ensure Funnel is enabled: tailscale funnel status
2. Check ACLs allow Funnel
3. Verify HTTPS certificate is valid

ngrok tunnel disconnecting

1. Upgrade to paid plan for stable URLs
2. Use custom domain: BETTERCALLCLAUDE_NGROK_DOMAIN
3. Check ngrok dashboard for connection limits

---

Development

# Clone the repo
git clone https://github.com/sns45/better-call-claude
cd better-call-claude

# Install dependencies
bun install

# Run in development mode
bun run dev

Testing locally

# Start the MCP server
bun run dev

# In another terminal, test with MCP inspector
npx @anthropics/mcp-inspector

---

Tech Stack

• Runtime: Bun - Fast JavaScript runtime
• Web Framework: Hono - Lightweight, fast web framework
• Phone: Telnyx / Twilio - Telephony APIs
• Speech: OpenAI Whisper - STT/TTS
• Transport: ngrok / Tailscale - Tunneling
• Protocol: MCP - Model Context Protocol

---

Contributing

PRs welcome! Please see CONTRIBUTING.md for guidelines.

---

License

MIT