Hi team, I’m using the direct Google Calendar integration in VAPI. I’ve set the correct timezone and calendar ID, but the tool is still returning all time slots as available. For example, I have two busy slots on a given day, but those times are still being offered as open. Could you please check if there’s an issue with the availability logic in the integration?

Suggestion: Double-check that your

startDateTime

and

endDateTime

fields are in ISO 8601 format and that the correct

calendarId

is being used in your tool configuration. For example:

json
{
  "startDateTime": "2025-08-12T09:00:00+00:00",
  "endDateTime": "2025-08-12T17:00:00+00:00",
  "timeZone": "UTC",
  "calendarId": "primary"
}

If these are set correctly and the issue persists, consider reaching out to Vapi support or their Discord community for further troubleshooting. [See documentation for details](https://docs.vapi.ai/tools/google-calendar) Source: - [Google Calendar Integration Documentation](https://docs.vapi.ai/tools/google-calendar)

had the same issue, fixed it with that in the global prompt: ## Current Time {{ "now" | date: "%b %d, %Y, %I:%M %p", "America/Toronto" }} ## Date & Time Handling Rules • Human-facing dates MUST be rendered exactly as

MMM dd, yyyy, hh:mm a

in the America/Toronto zone – Example: “Aug 05, 2025, 09:00 AM”. • Always create or parse times in the

America/Toronto

IANA zone, then: - When SPEAKING to callers ➜ format via strftime/Luxon

toFormat('MMM dd, yyyy, hh:mm a')

. - When CALLING tools or Google Calendar ➜ pass RFC 3339 strings that include the offset (e.g.

2025-08-05T09:00:00-04:00

). Never end ISO strings with “Z” unless you mean UTC. • Treat “hh = 01–11” + “PM” as afternoon/evening and “hh = 01–11” + “AM” as morning; “12:xx AM = 00:xx”, “12:xx PM = 12:xx”. If the user input omits AM/PM, ask for clarification. • Convert 24-hour inputs to 12-hour before speaking:

05:15

→ “05:15 AM”;

17:05

→ “05:05 PM”.

@Yanick Thanks for the help I'll give it a try

Checking if this is resolved/solved for you?

@Ch Adeel I just ran 5 tests in a row with different slots and it was working every time. What is you tool's description and how do you call your tool (give instruction to your tool) in the prompt?

Ch Adeel, could you please also share the call id where this issue occurred?

Problem is, now that we can't use a tool inside a conversation node, this cannot be used in a workflow assistant.

Did you get a solution for this? I have the same problem.

Liam, could you please share a call id? Also please be sure if you haven't already to give your assistant the datetime context for the current day.