schedule is not required, don't bother with it.
thermostatSetpoint follows the heating or cooling setpoint, when in auto and the device is idle it's updated based on the last operating mode.
Our drivers and the GH implementation look at and maintain a data variable "lastRunningMode" with "heat" | "cool" to track last operating mode.
You can blame GH's certification process for this, it was a requirement, and one of the reasons cert took as long as it did.
So if you have a thermostat driver, and you want it to work with GH, you need to maintain thermostatSetpoint properly as well as the data variable lastRunningMode
setting lastRuningMode: updateDataValue("lastRunningMode", "heat" | "cool")
reading lastRunningMode: getDataValue("lastRunningMode")
as an FYI, this value is stored in a data variable vs a state variable as data values can be read from apps whereas state variables cannot...
