@Aegon I am just suggesting to use Vapi AI for some research on yoru own because Vapi engineers are buried with issues. We are trying to get on their radar for an obvious Vapi bug that is preventing us from going live for a while now. Based on the Vapi AI: According to the documentation, for the GoHighLevel Check Availability Tool, the time parameters should be in epoch time milliseconds: - startDate: The start of the time range to check for availability (epoch time in milliseconds) - endDate: The end of the time range to check for availability (epoch time in milliseconds) Epoch time milliseconds is the number of milliseconds that have elapsed since January 1, 1970 (UTC). For example: Current time in epoch milliseconds would look like: 1697465875000 A date like "October 20, 2023 10:00 AM" would be: 1697810400000 To convert dates to epoch milliseconds in JavaScript, you can use: // Convert a date to epoch milliseconds const date = new Date('2023-10-20T10:00:00'); const epochMilliseconds = date.getTime(); // Current time in epoch milliseconds const now = Date.now(); When using the Check Availability tool, make sure both startDate and endDate are provided in this milliseconds format, and remember to specify the correct timezone in the timezone parameter (e.g., "America/New_York").