Know the time before hello

You have: Robin with a concierge and a complaint specialist, from Hand off complaints. The caller says “Friday”, and the agent knows which Friday.

What you add

A model does not know today’s date, and a server clock may be in another time zone. Prefetch reads what the call needs before the greeting and saves it into the state. First, three more state fields for the clock.

salon/state.py

class State(BaseModel):
    # The fields from the earlier pages stay. Add:
    booking_date: date | None = Field(
        None, description="Today's date in the salon's timezone, read once before the greeting."
    )
    booking_weekday: str = Field("", description="The weekday of booking_date, in English.")
    salon_local_time: time | None = Field(
        None, description="The salon's wall clock when the call began."
    )

Next, the prefetch and the function that builds each call’s state. These are the names the example uses.

salon/agent.py

from collections.abc import Mapping

from unmute_core.call import save_call_start
from unmute_core.prefetch import CallValue, Clock, Prefetch
from unmute_core.state import CallInfo, CallState

AGENT_ID = "salon-concierge"
PREFETCH = Prefetch(
    [
        Clock(
            "today",
            "Europe/Madrid",
            {"booking_date": "date", "booking_weekday": "day_of_week", "salon_local_time": "time"},
        ),
        CallValue("caller", "calling_number", ["customer_phone"]),
    ]
)

GREETING.check(PREFETCH)


async def new_call(
    call: CallInfo | None = None, dispatched: Mapping[str, object] | None = None
) -> CallState[State]:
    """Return a fresh call state, with today's date and the caller's number read in.

    Args:
        call: What the line carries. A web call's when None.
        dispatched: The dispatch's ``call_start`` object, when there is one.
    """
    state = CallState(State, confirm=CONFIRM, call=call or CallInfo(agent_id=AGENT_ID))
    save_call_start(state, dispatched)
    await PREFETCH.run(state)
    return state

Clock reads one time zone, once. Its assign maps each state value to a clock field: date, day_of_week or time.
CallValue copies a value the call carries, here the caller’s number from state.call.calling_number, into customer_phone. A browser call has no number, so that value stays empty.
save_call_start saves what the call was started with. It also reads UNMUTE_CALL_START, so a browser call can pretend to be a phone call.
GREETING.check(PREFETCH) refuses, at import, a greeting that names a value prefetch does not fill.

The number from caller ID is saved but not confirmed. It stays out of the prompts until verify_customer has read it back and the caller said yes. Then tell the concierge what day it is. Add this line to CONCIERGE_PROMPT.

Today is {{booking_weekday}}, {{booking_date}}, so "Friday" is the coming Friday.

Last, build the state with new_call where you built it by hand before.

# In entrypoint(), before the session starts.
state = await salon.new_call()

# In bot(), in place of CallState(State, confirm=salon.CONFIRM).
state = await salon.new_call()

A console or browser call has no caller ID, so state.call has no number. On a phone call, unmute_core.livekit.sip_call_info and unmute_core.pipecat.telephony_call_info read it from the carrier. Pass the result as call. Telephony shows how.

Try it

To try the caller ID path, simulate a phone caller, then start the agent.

export UNMUTE_CALL_START='{"call": {"direction": "inbound", "calling_number": "+34612345678"}}'

Say “Can I book a haircut for Friday?” Robin should offer times on the coming Friday, with no question about today’s date.
When Robin asks for your number, it should read back the one from caller ID and wait for a yes.

Why it works this way

The model reads today’s date from the state, so a call that starts at 11 pm in Madrid still gets Madrid’s date. The value is read once. A call that crosses midnight keeps the day it began on. Prefetch runs before the greeting. The first model request then has the date, and no tool call is spent to fetch it.

What you have now

Piece	File
State with the clock values	`salon/state.py`
`PREFETCH` and `new_call`	`salon/agent.py`
A call built with `new_call`	`livekit/agent.py`, `pipecat/bot.py`

Next: Quiet callers

Set the turn pace, nudge a quiet caller and end a long call.

Go deeper: Prefetch.

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Reference

Know the time before hello

What you add

Try it

Why it works this way

What you have now

Next: Quiet callers

​What you add

​Try it

​Why it works this way

​What you have now

Next: Quiet callers

What you add

Try it

Why it works this way

What you have now