Can a prompt replace OnceHub?

Build a booking system whose defining feature is a routing form in front of the calendar.

Calendar: connect one Google Calendar over OAuth with encrypted refresh tokens. Compute availability from working hours minus busy events, with buffers before and after, a minimum notice period, and a booking horizon. All arithmetic in UTC, rendered in the visitor's detected time zone with the zone named on screen.

Meeting types: each has a name, a duration, a location (a video link, a phone number, or an address), its own buffers and notice, and its own set of questions asked at booking.

The routing form, which is the point of this build. A short form shown before any availability is displayed: a handful of questions, each of type select, multi-select, number, or text with a match rule. Then an ordered list of routing rules, each a condition over the answers and a destination — a meeting type, an external URL, or a rejection message with an explanation. The first matching rule wins; a final catch-all rule is mandatory and cannot be deleted.

Making routing safe, which is where most of the work is:

- A rule tester: enter a set of answers, see which rule matches and where it sends. Required before a form can be published.
- Coverage analysis: enumerate the combinations of answers the questions allow and report which rule handles each, flagging any combination that falls through to the catch-all. A rule set with unreachable rules or unexpected fall-through is the failure mode that quietly costs you meetings, and the interface should refuse to let it be invisible.
- Every routed booking records which rule matched and the answers that triggered it, so a wrong outcome can be traced rather than guessed at.

Booking: reserve the slot transactionally so two simultaneous visitors cannot take the same time, create the calendar event with the answers in the description, and email confirmations to both sides with signed reschedule and cancel links that need no account.

Reminders: a scheduled job sending a reminder at a configurable interval before the meeting, with the send recorded so a restart cannot double-send.

Admin: booking list with the routing answers, a per-rule booking count (which tells you whether your qualifying questions are doing anything), an audit log, and a calendar reconnect flow.

Out of scope: multiple calendar providers, team round-robin or load balancing, payment collection, CRM integration, and any hosted multi-tenant deployment.