Test Mode

Test mode lets you interact with your agent in the terminal using pure text — no phone calls, no STT/TTS, no external services required. It simulates a phone conversation for rapid development.

Quick Start

import { Patter, Twilio, OpenAIRealtime } from "getpatter";

const phone = new Patter({ carrier: new Twilio(), phoneNumber: "+15550001234" });

const agent = phone.agent({
  engine: new OpenAIRealtime(),                         // OPENAI_API_KEY from env
  systemPrompt: "You are a helpful customer service agent for Acme Corp.",
  firstMessage: "Hello! Welcome to Acme Corp. How can I help you today?",
});

await phone.test({ agent });

This opens an interactive REPL:

============================================================
  PATTER TEST MODE
============================================================
  Agent: gpt-4o-mini-realtime-preview / alloy
  Provider: openai_realtime
  Call ID: test_a1b2c3d4e5f6
  Caller: +15550000001  →  Callee: +15550000002
------------------------------------------------------------
  Commands: /quit  /transfer <number>  /hangup  /history
============================================================

  Agent: Hello! Welcome to Acme Corp. How can I help you today?

  You: I need to return an item
  Agent: I'd be happy to help with your return...

Commands

Command	Description
`/quit`	End the test session.
`/hangup`	Simulate hanging up the call.
`/transfer <number>`	Simulate a call transfer.
`/history`	Print the full conversation history.

Using with `onMessage`

Test mode works with custom message handlers, exactly as they would work in production:

async function onMessage(data: Record<string, unknown>) {
  const userText = data.text as string;

  if (userText.toLowerCase().includes("cancel")) {
    return "Let me transfer you to our cancellation team.";
  }

  return `You said: ${userText}`;
}

await phone.test({ agent, onMessage });

The onMessage handler receives a single data object with text, call_id, caller, and history fields.

Using with Built-in LLM Loop

When no onMessage handler is provided and OPENAI_API_KEY is available (either from new OpenAIRealtime({ apiKey }) or the env var), test mode uses the built-in LLM loop with streaming responses:

const agent = phone.agent({
  systemPrompt: "You are a restaurant booking assistant.",
  tools: [
    {
      name: "check_availability",
      description: "Check table availability",
      parameters: {
        type: "object",
        properties: {
          date: { type: "string" },
          partySize: { type: "number" },
        },
      },
      webhookUrl: "https://api.example.com/availability",
    },
  ],
});

await phone.test({ agent });

The LLM loop supports tool calling — tools are executed via their configured webhooks just like in production.

Event Callbacks

Test mode fires the same lifecycle callbacks as serve():

await phone.test({
  agent,
  onCallStart: async (event) => {
    console.log(`Test call started: ${event.call_id}`);
  },
  onCallEnd: async (event) => {
    console.log(`Test call ended: ${event.call_id}`);
    const transcript = event.transcript as Array<unknown>;
    console.log(`Transcript: ${transcript.length} messages`);
  },
});

Test mode is designed for development only. It does not use any external APIs (except OpenAI for the LLM loop when no onMessage is provided).

Get Started

Setting up Patter

Observability

Integrations

Development

Test Mode

Test Mode

Quick Start

Commands

Using with `onMessage`

Using with Built-in LLM Loop

Event Callbacks

​Test Mode

​Quick Start

​Commands

​Using with onMessage

​Using with Built-in LLM Loop

​Event Callbacks

Test Mode

Quick Start

Commands

Using with `onMessage`

Using with Built-in LLM Loop

Event Callbacks