### Answer I don't have specific documentation on integrating Retell AI directly with Go High Level (GHL) calendars. The built-in calendar tools in Retell AI are designed for Cal.com integration, not GHL natively. However, based on community discussions, here's the general approach for GHL calendar booking: Use a Custom Function: The built-in booking function is limited in functionality. [(1) ]() For Go High Level integration, you'll need to set up a custom function (custom tool) that calls the GHL API. How Custom Functions Work: - In Conversation Flow agents, you can add a custom function and configure it to make GET, POST, PUT, PATCH, or DELETE requests with custom headers and query parameters. [(2) ]() - You would create a custom function that hits GHL's API endpoints for checking availability and booking appointments. Community Experience: Some users have successfully built multi-agent appointment scheduling systems using Retell AI and Go High Level as the CRM, including appointment setter bots, confirmation agents, and rescheduling agents. [(3) ]() Check out these potentially useful sources: - [GHL Integration]() - [Custom Function Docs]() - [Hire certified Retell partner]() Would you like a general answer on how to structure a custom function for calendar booking?

​ To learn more, see the sources I considered: [[1] calendar appointment booking through retell](https://discord.com/channels/1186424376300679209/1250814023067500657) [[2] Platform Changelogs | Retell AI](https://www.retellai.com/changelog) [[3] Discord message from @nicholasbayerle_80902 on 2025-10-20](https://discord.com/channels/1186424376300679209/1186462578310910112/1429906217437888512) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.