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 transport - Tailscale Funnel with guided auto-setup
- 🗣️ 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 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

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

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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

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Tailscale Funnel provides free, stable public URLs for receiving webhooks from your phone provider.

> Why Tailscale? Free unlimited tunnels, stable URLs (no random subdomains), enterprise-grade security.
>
> Path: Better Call Claude uses /bcc path (e.g., https://your-hostname.ts.net/bcc) to avoid conflicts with other services.

First-time setup (automated):

When you first start the MCP server, it will guide you through setup:

1. Install Tailscale (if not installed):
``bash
# macOS
brew install tailscale

# Linux
curl -fsSL https://tailscale.com/install.sh | sh
`

2. Authenticate - The server will auto-run tailscale up and open your browser

3. Enable Funnel - Visit the URL shown in the terminal to enable Funnel on your tailnet (one-time admin step)

That's it! The server handles the rest automatically.

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`bash


Quick start with bunx (recommended)

bunx better-call-claude

Or install globally

bun install -g better-call-claude
better-call-claude
`

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Add to ~/.claude/settings.json:

`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-..."
}
}
}
}
`

> Note: Tailscale setup is automatic on first run. The server will guide you through installation and authentication if needed.

Restart Claude Code. Done!

---

Environment Variables

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| 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 |

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| Variable | Default | Description |
|----------|---------|-------------|
| TAILSCALE_HOSTNAME | auto-detected | Override Tailscale hostname |

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| 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

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#### 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

---

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#### 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."

---

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#### 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."

---

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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"

---

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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-tailscale-url}/bcc/webhook/twilio/whatsapp
4. Add to your config:
`json
"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 │
│ (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) │
└──────────────────────────────────┘
`

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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

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#### receive_inbound_call
Accept and process an incoming call from the user.

#### initiate_call
Start a phone call to the user.

`typescript
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.

`typescript
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).

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

#### end_call
End an active call.

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

#### get_call_status
Check status of current or recent calls.

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

---

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#### receive_inbound_message
Check for incoming SMS or WhatsApp messages.

`typescript
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.

`typescript
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.

`typescript
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).

`typescript
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.

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

---

Costs

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| 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

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

Typical SMS exchange: ~$0.01-0.02/exchange

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

Typical WhatsApp exchange: ~$0.01-0.02/exchange

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| Service | Cost |
|---------|------|
| Phone number | ~$1/month |
| Tailscale Funnel | Free |

---

Security Considerations

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- Funnel creates a public endpoint but traffic routes through Tailscale's secure network
- Integrates with SSO/SCIM for enterprise use
- Audit logs available in Tailscale admin console
- Webhook signatures verified by default

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

---

Troubleshooting

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#### 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 Tailscale Funnel 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

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#### 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

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#### 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)

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#### "Tailscale not running"
1. macOS: Open the Tailscale app from Applications
2. Linux: sudo systemctl start tailscaled && tailscale up

#### "Funnel not enabled"
1. Visit the URL shown in the terminal to enable Funnel
2. Or go to https://login.tailscale.com/admin/acls and add Funnel capability

#### Funnel starts but webhooks don't work
1. Check tailscale funnel status shows /bcc pointing to your port
2. Verify your phone provider webhook URL matches the Tailscale URL (with /bcc path)
3. Test with curl https://your-hostname.ts.net/bcc/health

---

Development

`bash


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
`

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`bash


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: Tailscale Funnel - Public URL tunneling
- Protocol: MCP - Model Context Protocol

---

Contributing

PRs welcome! Please see CONTRIBUTING.md for guidelines.

---

License

MIT