There are reference on call monitoring for RingCentral, you can refer once:

https://netstorage.ringcentral.com/datasheets/call_monitoring_datasheet.pdf

https://www.ringcentral.com/call-monitoring.html

https://www.ringcentral.com/office/features/call-monitoring/overview.html

Hi Ken, there is no option for this. However, during your live call monitoring, you can whisper or coach your agent. Call coaching allows you to speak directly to the extension you are coaching while they are in a call without transmitting audio to the other party. It would be the best opportunity to let them know they are monitored.

For feature requests, you may add it in our Ideas Portal at https://ideas.ringcentral.com/.