WebSocket Transport

{"type": "context", "text": "The caller's order shipped today.", "role": "system"}

{"type": "context", "text": "Where is my order?", "role": "user", "trigger_response": true}

{"type": "tool_call", "event_id": 42, "tool_call_id": "call_7f3a", "name": "check_account_balance", "arguments": {"account_id": "417"}, "expects_response": true}

{"type": "tool_result", "tool_call_id": "call_7f3a", "result": {"balance_usd": 128.4}}

# pip install websockets
import asyncio
import json

import websockets

from create_call import create_call  # from step 1

FRAME_BYTES = 640  # 20 ms of 16 kHz signed 16-bit mono PCM


async def run_call() -> None:
    call = create_call({"customer_name": "Ada"})

    async with websockets.connect(call["websocket_url"], max_size=2**20) as ws:
        started = asyncio.Event()

        async def send_audio() -> None:
            """Replace read_frame() with your telephony leg's audio source."""
            await started.wait()  # no audio before call.started
            while True:
                frame = await read_frame(FRAME_BYTES)
                if frame is None:
                    await ws.send(json.dumps({"type": "hangup"}))
                    return
                await ws.send(frame)

        async def receive() -> None:
            async for message in ws:
                if isinstance(message, bytes):
                    await play_frame(message)
                    continue

                event = json.loads(message)
                kind = event["type"]

                if kind == "call.started":
                    started.set()
                elif kind == "ping":
                    await ws.send(json.dumps({"type": "pong", "event_id": event["event_id"]}))
                elif kind == "interruption":
                    await drop_buffered_playback()
                elif kind == "transcript" and event["final"]:
                    print(f'{event["role"]}: {event["text"]}')
                elif kind == "tool_call":
                    result = await run_client_tool(event["name"], event["arguments"])
                    if event.get("expects_response", True):
                        await ws.send(
                            json.dumps(
                                {
                                    "type": "tool_result",
                                    "tool_call_id": event["tool_call_id"],
                                    "result": result,
                                }
                            )
                        )
                elif kind == "transfer":
                    await transfer_on_pbx(event["destination"], event["label"])
                elif kind == "call.ended":
                    print(f'call ended: {event["reason"]}')
                    return

        sender = asyncio.create_task(send_audio())
        try:
            await receive()
        finally:
            sender.cancel()


asyncio.run(run_call())