A quick question. A creature moved out of melee range causing an opportunity attack. Our rogue used Booming Blade with his short sword for the opportunity attack. The question, can the rogue use Booming Blade with this opportunity attack?
No, they can't, unless they have some special feature that allows them to cast a spell in place of an opportunity attack. The most common example of this is the War Caster feat.
In the absence of a feature like that, an opportunity attack allows you to make one melee attack or unarmed strike. It doesn't allow you to cast a spell (even one like Booming Blade that involves making an attack).
Can you use True Strike with Extra Attack, Opportunity Attack, Sneak Attack, and other weapon attack options?
True Strike doesn’t work with Extra Attack or any other feature that requires the Attack action. Like other spells with a casting time of an action, casting True Strike requires you to take the Magic action, not the Attack action. Similarly, unless a special feature allows you to do so, you can’t cast True Strike when making an Opportunity Attack.
However, an attack made as part of True Strike works with Sneak Attack so long as it fills the normal requirements for that feature. For example, if you have the Sneak Attack feature and cast True Strike with a Finesse weapon, you can deal Sneak Attack damage to the target of the attack if you have Advantage on the attack roll and hit.
War Caster doesn't allow for the casting of Booming Blade since the spell in question must be cast at the target creature and Booming Blade has a range of self.
War Caster doesn't allow for the casting of Booming Blade since the spell in question must be cast at the target creature and Booming Blade has a range of self.
This is neither clear from the rulebooks nor anything like universally agreed on. (And there's a very solid intent-of-the-rules argument that they should.)
The rulebooks are actually quite clear on this and of course when it comes to the RAW it really doesn't matter if people agree or not, it only matters what the text actually says.
Both the 2014 version and the 2024 version of the War Caster feat explicitly require that the spell is cast at the provoking creature. This is thematically consistent with the 5e concept of what an opportunity attack represents in the game which is when a creature lashes out at another creature in response to that other creature attempting to hastily retreat away from a melee combat engagement. As such, the wording appears to be extremely intentional.
The idea is that the War Caster creature is meant to directly target the provoking creature with a spell such as Fire Bolt (at disadvantage) or Shocking Grasp or Charm Person or Sacred Flame or Chill Touch or Chromatic Orb or even something like Witch Bolt, for example.
Something like the Read Thoughts effect of the Detect Thoughts spell (pretend for a moment that this is the spell's only possible effect) would not qualify even though the provoking creature is being "targeted" in the 5e Rules Glossary sense. The reason is that the spell is not being cast at that creature, it is being cast at the spellcaster. If you could somehow cast Scrying as an action this also would not qualify for similar reasons.
But probably the best two examples of spells from the 2024 PHB which are disqualified from this interaction for the same reason as Booming Blade would be True Strike and Vampiric Touch. In both of those cases, a single creature is being "targeted", but the spell is not being cast at that creature. Instead, those spells have a range of self, meaning, they are spells which create effects that buff the spellcaster in a particular way. Note that True Strike is actually a Divination spell -- the concept is that the spell mentally empowers the spellcaster while performing a specific activity.
War Caster is already powerful enough, especially when people begin trying to claim that these opportunity attacks can be made against their allies, which is a whole separate rabbit hole. There's no need to make it even more powerful by ignoring some of the restrictions that the text is providing.
War Caster doesn't allow for the casting of Booming Blade since the spell in question must be cast at the target creature and Booming Blade has a range of self.
A quick question. A creature moved out of melee range causing an opportunity attack. Our rogue used Booming Blade with his short sword for the opportunity attack. The question, can the rogue use Booming Blade with this opportunity attack?
No, they can't, unless they have some special feature that allows them to cast a spell in place of an opportunity attack. The most common example of this is the War Caster feat.
In the absence of a feature like that, an opportunity attack allows you to make one melee attack or unarmed strike. It doesn't allow you to cast a spell (even one like Booming Blade that involves making an attack).
pronouns: he/she/they
The SAC has this answer. It's using True Strike for the explanation, but IMO the cantrip is similar to Booming Blade (or Green-Flame Blade and Vengeful Blade).
That "special feature" might be War Caster.
EDIT: Since the question is about Booming Blade , this is the 2014 SAC answer that mentions it: Can you use green-flame blade and booming blade with Extra Attack, opportunity attacks, Sneak Attack, and other weapon attack options?
War Caster doesn't allow for the casting of Booming Blade since the spell in question must be cast at the target creature and Booming Blade has a range of self.
This is neither clear from the rulebooks nor anything like universally agreed on. (And there's a very solid intent-of-the-rules argument that they should.)
Ask your DM.
The rulebooks are actually quite clear on this and of course when it comes to the RAW it really doesn't matter if people agree or not, it only matters what the text actually says.
Both the 2014 version and the 2024 version of the War Caster feat explicitly require that the spell is cast at the provoking creature. This is thematically consistent with the 5e concept of what an opportunity attack represents in the game which is when a creature lashes out at another creature in response to that other creature attempting to hastily retreat away from a melee combat engagement. As such, the wording appears to be extremely intentional.
The idea is that the War Caster creature is meant to directly target the provoking creature with a spell such as Fire Bolt (at disadvantage) or Shocking Grasp or Charm Person or Sacred Flame or Chill Touch or Chromatic Orb or even something like Witch Bolt, for example.
Something like the Read Thoughts effect of the Detect Thoughts spell (pretend for a moment that this is the spell's only possible effect) would not qualify even though the provoking creature is being "targeted" in the 5e Rules Glossary sense. The reason is that the spell is not being cast at that creature, it is being cast at the spellcaster. If you could somehow cast Scrying as an action this also would not qualify for similar reasons.
But probably the best two examples of spells from the 2024 PHB which are disqualified from this interaction for the same reason as Booming Blade would be True Strike and Vampiric Touch. In both of those cases, a single creature is being "targeted", but the spell is not being cast at that creature. Instead, those spells have a range of self, meaning, they are spells which create effects that buff the spellcaster in a particular way. Note that True Strike is actually a Divination spell -- the concept is that the spell mentally empowers the spellcaster while performing a specific activity.
War Caster is already powerful enough, especially when people begin trying to claim that these opportunity attacks can be made against their allies, which is a whole separate rabbit hole. There's no need to make it even more powerful by ignoring some of the restrictions that the text is providing.
I don't agree.
I'm not going to rehash the same arguments here, but what Range means was recently explained in True strike and overthinking it. - Rules & Game Mechanics. War Caster was also mentioned there.