Bookends: work before the first word and after the last

A surprising amount of what a voice agent does has nothing to do with talking. Looking up who is calling. Checking consent and whether it is a legal hour to call them back. Writing the summary. Syncing the CRM. Sending the follow-up text. Working out what the call cost.

None of that needs the caller on the line. Bookends is the voice agent pattern that moves it out of the live conversation, to before the first word and after the last.

Use it when

Almost always. This is the one pattern nearly every production agent should have.

Before the call: identify the caller from their number, load their history and preferences, check consent and the calling window for outbound calls, pick the right agent and language. All of it hides inside ring time.

After the call: summary, structured extraction (what was ordered, what was promised), CRM sync, follow-up text or email, call scoring, and the cost receipt for billing.

For an agency, the after half is what the client actually sees. Transcripts are nice. A summary in their CRM within a minute of hanging up is what renews the contract.

Latency

The briefing hides inside ring time. The wrap-up adds nothing to the call, because the caller is already gone.

Build it on LiveKit

The before half runs in the job entrypoint, before the session starts. The after half is a shutdown callback.

from livekit.agents import AgentServer, AgentSession, JobContext

server = AgentServer()


@server.rtc_session()
async def entrypoint(ctx: JobContext) -> None:
    # Before the first word: hidden inside ring time.
    caller = await crm.lookup(phone=caller_number(ctx))
    if not await consent.allowed(caller):
        return

    session = AgentSession(...)

    # After the last word: the caller is gone, take your time.
    async def wrap_up() -> None:
        summary = await summarise(session.history)
        await crm.log_call(caller.id, summary)
        await sms.send(caller.phone, follow_up_text(summary))

    ctx.add_shutdown_callback(wrap_up)
    await session.start(agent=Receptionist(caller=caller), room=ctx.room)

ShipVoice Pro already does caller identity, the dial gate, call reporting and the end-of-call notification this way.

How it combines

Bookends wrap every other pattern. The briefing decides which agent picks up, Solo for a new caller, the VIP desk for a regular. The wrap-up collects what every phase of a Relay produced and what the Observer flagged. Attach caller memory and guardrails as capabilities here: memory loads in the briefing and saves in the wrap-up, and compliance checks run before any outbound dial.