Hi there, If your Google Calendar shows busy times as available, this is usually caused by a timezone mismatch. The checkAvailability tool expects the start and end times in UTC, so if your prompt or assistant uses local time without converting, it will treat busy times as free. Here’s a prompt that has helped many users avoid double booking:

## scheduling appointments
ask the user what day and time they want to schedule an appointment. assume all appointments are 1 hour long and are all in PST timezone (UTC-7). once you get the desired day and time for the appointment, convert the day and time to UTC+0 timezone equivalent, then use the 'google_check' tool to check if the desired day and time is available. if it is not available, apologize then suggest a different time. if it is available, tell the user it is available and ask if they would like to schedule the appointment for this time. if they say yes, use the 'google_schedule' tool to create the event for the day and time in the UTC+0 timezone equivalent. if they say no, then tell them it's okay and you understand their decision.

Key takeaway: Always convert times to UTC before calling the tool. If after applying this you still see the issue, please let us know — we’re happy to help troubleshoot further.