@JeremyECrawford Does casting a bonus action spell prevent reaction spells just on the player's own turn, or for the rest of the round?
— Samuel Rodda (@QueerSeer) April 16, 2016
Casting a bonus action spell limits your spellcasting options on your turn—no effect on an off-turn reaction. #DnD https://t.co/BrPU3ZbYzO
— Jeremy Crawford (@JeremyECrawford) April 16, 2016
@JeremyECrawford @QueerSeer does that include readying a spell? I can see that being abusable
— Joran Dox (@NightFantomJ2) April 16, 2016
If you cast a bonus action spell, the only type of spell you can ready that turn is a 1-action cantrip. #DnD https://t.co/TXCIAqhc0v
— Jeremy Crawford (@JeremyECrawford) April 22, 2016
@o76923turn or round? If you bonus on your turn & ready for later in the round, it’ll be another turn. With Ready, you begin casting the spell on your turn, not when you use the reaction later. @NightFantomJ2 @QueerSeer
— Jeremy Crawford (@JeremyECrawford) April 22, 2016
I assume the opposite would be true too, i.e. that if you ready a bonus action spell, the only type of spell you can cast that turn is a 1-action cantrip. Right?
You cannot ready a spell that has a casting time of one action. The “Ready” action takes your Action, and allows you to take the readied action as a reaction to the specified trigger.
You can totally Ready a spell that has a casting time of one action — that’s literally the point of Ready Action ready to spell casting. What JC clarified via the other rules for Bonus Actions is that you can’t ready a *Bonus Action* for later release via your Reaction: you can only Ready an Action (spell). (Unless you miss-typed and meant to to say “…cannot ready… casting time of one [bonus] action…”.)
You can only Ready an Action (spell) — you can’t Ready Bonus Actions (spells). You can cast a BA spell on your turn to do >whatever it does<, and then Ready a cantrip for later in the round/into the next round before your initiative comes back around again, but you can't do the opposite: Ready a BA for later use while cantrip-ing on your turn.