Patter: Tool Calling

Webhook-backed function calling -- let your agent look up customers, create tickets, and call any external API during a live phone call.

Part of the Patter Voice AI SDK.

Prerequisites

• Twilio account with a phone number
• OpenAI API key with Realtime access

Quick Start

Python

cd python
cp ../.env.example .env   # fill in your keys
pip install -r requirements.txt
python main.py

TypeScript

cd typescript
cp ../.env.example .env   # fill in your keys
npm install
npx tsx main.ts

Environment Variables

Variable	Required	Description
OPENAI_API_KEY	Yes	OpenAI API key with Realtime access
TWILIO_ACCOUNT_SID	Yes	Twilio account SID
TWILIO_AUTH_TOKEN	Yes	Twilio auth token
TWILIO_PHONE_NUMBER	Yes	Your Twilio phone number (E.164)
WEBHOOK_URL	No	Public URL for webhooks (auto-tunneled if omitted)

What This Demonstrates

• Defining tools with webhookUrl to delegate execution to your backend
• Agent using tools during live phone calls
• Patter.tool() helper for building tool definitions
• CRM lookup + support ticket creation as example tools

Next Steps

• Inbound Agent — answer calls with AI
• Outbound Calls — place calls with AMD
• Custom Voice — pipeline mode with Deepgram + ElevenLabs
• Full documentation
• All templates

License

MIT