Source of spousal conflict.
Wife: I want a fire! We had this installed so we could actually use it! (The old fireplace leaked gas and we had it disconnected when we bought the house)

Me: But it will mess up my boiler control algorithm!

(Needless to say, the fireplace is on now.)

@dave_andersen Boiler control just needs another input. Plenty of opportunity to test in the coming weeks.

@khsinclair hmmm. Clearly you're right.

Probably the easiest thing would be a thermometer right next to / attached to the fireplace to infer activity. Or a power meter on its electrical but the thermometer is easier to integrate.