What built-in tools are
Built-in tools come with the platform. You attach them to a Conversation step on the Finn's call flow canvas and fill in a few fields. You don't host anything. For your own endpoints, use custom tools.
| Tool | What it does | You provide |
|---|---|---|
| Check Calendar | Reads open slots from a Cal.com event type | Cal.com API key, event type ID, timezone |
| Book Calendar | Books a slot on a Cal.com event type | Cal.com API key, event type ID, timezone |
| Call Transfer | Hands the live call to a phone number | A number in E.164 format |
Ending the call is the End Call step, not an attachable tool. It's covered at the end of this page.
Like every tool, these only run on a Finn with a call flow canvas. See tools overview.
Calendar tools
Check Calendar and Book Calendar work with Cal.com only. They call the Cal.com API directly with your key. Google Calendar and other calendars can't be booked from a call flow.
Both tools take the same fields:
| Field | What to enter |
|---|---|
| Cal.com API key | A key from your Cal.com account. The tool won't work without it, and the canvas flags a step that has a calendar tool with no key. |
| Event type ID | The numeric ID of the Cal.com event type to read and book |
| Timezone | An IANA time zone, for example Asia/Kolkata. Defaults to UTC when left empty. |
| Filler (optional) | What the Finn says while it waits on Cal.com |
The key is sent from the server, never to the caller. It is stored in the call flow, though, so it appears in Export JSON. Treat an exported file as a secret.
Most booking flows attach both tools to the same step, with a prompt along the lines of "Ask for a preferred day, check the calendar, offer what's open, then book the one the caller picks."
Check Calendar
The Finn picks a date from the conversation and asks Cal.com for open slots on that day and the next. It then offers the caller the two or three earliest, not the full list.
If nothing is open, the Finn is told so and won't invent times. It tells the caller nothing is free in that window and asks about another date.
Default filler: "Let me check the calendar, one moment…". Timeout: 6 seconds.
Book Calendar
To book, the Finn needs three things from the caller:
| Value | Where it comes from |
|---|---|
| Slot start | The slot the caller picked |
| Name | Asked on the call |
| Asked on the call. Cal.com requires it. |
The caller's phone number is added to the booking automatically: the number dialled on an outbound call, the caller's number on an inbound one.
Getting an email address right by voice is hard. Tell the Finn in the step prompt to read the address back and confirm it before booking.
Default filler: "Great, booking that for you now…". Timeout: 8 seconds. If Cal.com reports no host available at that time, the Finn asks the caller for another time.
Call Transfer
Hands the live call to a number you set and ends the Finn's part of the call. Fields: Transfer to number (E.164, for example +15551234567) and an optional Message before transfer. Configuration and failure modes are on transfer.
End Call
End Call is a step. Add it from Add step and connect a Conversation step to it. The condition on that connection tells the Finn when to hang up, for example "caller has no more questions".
Its one field is Goodbye message, the last thing the Finn says. If you leave it empty, the Finn says "Thanks for calling — goodbye!". See workflow nodes.
Testing
Use Test → Phone call. Only a real call runs the tools: it confirms the Cal.com key and event type are right, that a booking shows up in Cal.com, and that a transfer reaches the destination. Simulation chat doesn't run tools. See testing a workflow.