Does a cantrip only count as “cast a spell” then? A caster can’t use a cantrip on an opportunity attack?

@corymacdonaldSo wait? Does a cantrip only count as “cast a spell” then? A caster can’t use a cantrip on an opportunity attack? Correct. A cantrip is a spell.

— Jeremy Crawford (@JeremyECrawford) March 23, 2015

@corymacdonaldA cantrip being a spell doesn’t bother me definitionally. A cantrip being unusable on an OA does. I encourage creating a house rule if you want all spellcasters to be able to use cantrips for OAs. @WiscoDwarf

— Jeremy Crawford (@JeremyECrawford) March 23, 2015

@corymacdonald I didn’t realize it’d nerf War Caster. It was how I thought about cantrips. Clearly baked in. I’m good now. Excellent! @WiscoDwarf

— Jeremy Crawford (@JeremyECrawford) March 24, 2015