The same principle, whatever the calendar
A voice agent only offers what the calendar shows it as free, and divides it up according to the rules you give it. So it needs three things: to know where to write the appointment, how long it lasts, and when not to book it. Outlook and Cal.com answer these questions in different ways. Outlook is a calendar: it knows what is busy, not what you sell. Cal.com is a booking tool: it knows your appointment types and their limits.
If you work in Google Calendar, our Google Calendar guide sets out the same approach. And for the order of questions on the phone, see the guide to booking appointments by phone.
Microsoft 365 and Outlook
One calendar per person, preferably their own
In Microsoft 365, each member of staff usually has their own mailbox and primary calendar. That is the calendar to use for their appointments. Microsoft points out that, in classic Outlook, events in additional calendars don't appear in the Scheduling Assistant: only the primary calendar affects your availability.
An additional calendar is still useful for a resource, a meeting room or a vehicle, or to keep an activity separate. In new Outlook, Microsoft gives the following steps: the “Home” tab, the “Add calendar” button below the grid, “Create blank calendar”, a name, then “Save”.
The “Show as” status: watch out for all-day events
Every Outlook event has a status: free, working elsewhere, tentative, busy or away (out of office). The labels vary between versions. Microsoft points out two default behaviours:
- meetings and appointments automatically show as busy;
- new all-day events show as free.
The consequence is immediate: time off entered as an all-day event blocks nothing until you change its status to “busy” or “away”. Check every day off, every training course, every closure day. For breaks and admin time, use “busy” rather than “tentative”: a slot that the agent mustn't offer should leave no room for doubt.
Working hours
Outlook lets you set working hours and a work location, but this feature requires a work or school account with an eligible Microsoft 365 subscription, and it is mainly used to inform colleagues who are scheduling a meeting. Give the agent your opening hours, day by day, in its rules.
Sharing
In Outlook on the web, sharing is done from the calendar: “Share”, choose the calendar, the person's name or email address, the permission level, then “Share”. Microsoft offers these levels:
| Level | What the person can do |
|---|---|
| Can view when I'm busy | See your busy slots, without details |
| Can view titles and locations | Also see the title and location |
| Can view all details | Read everything |
| Can edit | Edit your calendar |
| Delegate | Edit and act on your behalf |
Your organisation may restrict sharing to internal people. And a calendar shared via an ICS link stays read-only, even if you have granted edit rights: nobody can write to it that way.
Cal.com
One event type per service
Cal.com is organised around event types. Each one has a title, a description, a duration, a booking URL and a location. Create one for each genuinely different service: “First appointment”, “Follow-up appointment”, “Phone catch-up”. For a team, the assignment tab lets you choose a collective event, round robin or a managed event.
Availability
Schedules are set in “Availability”. The schedule marked “Default” applies to any event type that doesn't have its own; there you switch on your hours day by day, and you can add several time slots in the same day, which leaves the lunch break out. For time off or a closure, a date override (“Add an override”) with the “Mark unavailable (All day)” option closes the day. Finally, check the time zone, at the top right of the schedule. Several schedules can coexist, and each event type can use its own.
Limits
An event type's limits tab sets buffer time before or after the appointment, minimum notice before booking, the number of bookings allowed over a period and how far ahead people can book. These are exactly the rules an agent needs to know.
Aligning the phone with your online rules
| Rule | Outlook | Cal.com | To give the agent |
|---|---|---|---|
| Duration per service | Not in the calendar | Event type | Yes, per appointment type |
| Buffer time | Not in the calendar | Limitations | Yes |
| Minimum notice | Not in the calendar | Limitations | Yes |
| Number per day | Not in the calendar | Limitations | Yes |
| Time off, breaks | “Busy” status | Date override, time slots | Read from the calendar |
Write these rules once, and give the same ones to the online page and to the agent: customers will find the same policy whether they click or call.
What Sayelo does with Outlook and Cal.com
Microsoft 365 and Cal.com are natively connected on every plan, like Google Calendar; other calendars can be looked at on request. During the call, Sayelo reads the calendar in real time, offers slots that follow your rules (duration per appointment type, open slots, buffer time, minimum notice, number of appointments per day), and a double-booking lock reserves the slot for whoever confirms first. It sends the confirmation by SMS and the reminder the day before, and handles rescheduling and cancellation if you allow it.
After the call, you receive the summary by email, and the call can go into your CRM: our guide to Sellsy, monday.com and webhooks explains how. For a solicitor's or accountant's practice, the agent can also be set never to confirm to a third party that a case or an appointment exists.
Ready in 5 minutes, with setup guided by your agent; the calendar is then connected in “What it does” → “Connected calendar”. To see how Sayelo compares with other solutions, particularly on calendars, read our comparison of AI voice agents for small businesses, then the pricing, with a 14-day free trial.
