[5E] Interrupting a Spellcaster via Ready Action

[DND_Reborn]

Armour Class works against combat spells, Saving Throws too. The Shield spell would be one of those specific effects that I mentioned in the post you quoted, Readied actions aren't.

Of course there are things like Defensive Duelist, a reaction further increasing your chance of being misses (i.e. interrupting the attack). You fail to realize that you are still casting the spell, but your efforts are ruined by another's action.

Consider this, your target is standing in a doorway. He readied his action to move behind the door (no longer in sight so no longer a target for your spell) as soon as you begin to cast a spell. You start your spell action, his reaction interrupts you, and is now no longer a valid target--you have to choose another.

Since you ignored the rest of my post about the time necessary to actually cast a spell, you are fine with accepting the over simplified version in 5E. Many people aren't. It makes no sense for magic to be faster than an eye blink. Take Burning Hands for instance, how long does it take you to put your hands together with fingers spread wide? About the same amount of time it would take a fighter with readied weapon to swing at you.

To say "readied actions aren't" is your interpretation. A readied action interrupts on another's turn. The precise wording of the triggering event is vital. If the triggering event is a caster is casting a spell, our interpretation is the caster can be stopped. If the triggering event was a caster has cast a spell, then you are acting as soon as he is finished.

Remember, although D&D uses a turn-based system, all of your actions must be assumed to happen over the course of the 6-second round. You are not going to move, attack, move, or whatever in an instant of time. A spell caster might take a moment or two in order to get out components, a second to make a hand motion or something, all while reciting the verbal component. I'm not saying that has to take the entire 6 seconds, after all a caster can still move their speed as well. All these actions happen at the same time everything else is going on.

Also, to say you can stop a spell with Counterspell as a reaction, but not use your reaction to take a readied action to interrupt the same spell, is illogical.

 

[MarkB]

Since you ignored the rest of my post about the time necessary to actually cast a spell, you are fine with accepting the over simplified version in 5E. Many people aren't. It makes no sense for magic to be faster than an eye blink. Take Burning Hands for instance, how long does it take you to put your hands together with fingers spread wide? About the same amount of time it would take a fighter with readied weapon to swing at you.

Then, if that fighter is swinging his sword as a readied action in response to your spellcasting, it makes perfect logical sense that his swing won't connect until after you finish casting, because you started casting first, and then he started swinging.

Also, to say you can stop a spell with Counterspell as a reaction, but not use your reaction to take a readied action to interrupt the same spell, is illogical.

Why? Not all reactions are exactly alike. The Ready action has a specific caveat about how soon you can use your reaction. Counterspell does not.

 

[Nickolaidas]

I think that dnd4vr makes a solid point. And to take it a step further, I think that the character who rolled a higher initiative gets to interrupt those who rolled lower.

So yes, if the PC Fighter (who plays before the Grimlock), says that he readies an action to hit the Grimlock the second the creature looks that it's about to hit the PC Wizard, then yes, I would rule that the PC FIghter would throw his spear to the Grimlock first, and if the Grimlock survives, THEN he gets to swing his club at the wizard.

So yeah, the way I see it, Ready Action *IS* interruption of someone else's (who rolled lower in his initiative) action.

 

[DND_Reborn]

Then, if that fighter is swinging his sword as a readied action in response to your spellcasting, it makes perfect logical sense that his swing won't connect until after you finish casting, because you started casting first, and then he started swinging.

Why? Not all reactions are exactly alike. The Ready action has a specific caveat about how soon you can use your reaction. Counterspell does not.

Let's look at Counterspell. "You attempt to interrupt a creature in the process of casting a spell."

The process of casting a spell. It takes time, no matter how little or how much, but 5E doesn't measure "time" actions take. Moving 30 feet, for instance, takes time during that 6-second round. It is not instantaneous. Making an attack takes time. We don't know how long this time is because 5E decided to simplify it, thinking it really didn't matter. But for many of us it does.

You can use your reaction to Counterspell, and I have a readied action to use my reaction to try to hit you and stop the spell (possibly, you still get to make a concentration check in our game). What is the difference? Where is the problem?

I would still have to succeed in the attack roll, and you would still have to fail in the concentration check. Assuming a 50/50 for each event, it is only a 1 in 4 chance your spell will be stopped, and that requires me to ready my action specifically for that!

With Counterspell, your chances are most likely better than 25% that you will stop the spell.

 

[Torquar]

Since you ignored the rest of my post about the time necessary to actually cast a spell, you are fine with accepting the over simplified version in 5E. Many people aren't. It makes no sense for magic to be faster than an eye blink. Take Burning Hands for instance, how long does it take you to put your hands together with fingers spread wide? About the same amount of time it would take a fighter with readied weapon to swing at you.

Yes, about the same amount of time. And since the caster started first, they finish first. The attack lands after the spell is finished.

To say "readied actions aren't" is your interpretation. A readied action interrupts on another's turn. The precise wording of the triggering event is vital. If the triggering event is a caster is casting a spell, our interpretation is the caster can be stopped. If the triggering event was a caster has cast a spell, then you are acting as soon as he is finished.

Remember, although D&D uses a turn-based system, all of your actions must be assumed to happen over the course of the 6-second round. You are not going to move, attack, move, or whatever in an instant of time. A spell caster might take a moment or two in order to get out components, a second to make a hand motion or something, all while reciting the verbal component. I'm not saying that has to take the entire 6 seconds, after all a caster can still move their speed as well. All these actions happen at the same time everything else is going on.

A caster can manage two spells a round plus movement with 1 action cantrips and a bonus action spell. Combat magic in 5e is fast.

Also, to say you can stop a spell with Counterspell as a reaction, but not use your reaction to take a readied action to interrupt the same spell, is illogical.

There is no "Interrupt Casting" action in 5e, nor is casting a 1 action spell subject to Concentration checks for suffering damage. An unprotected Wizard swimming through acid isn't required to make a Concentration check to cast a 1 action spell.

 

[DND_Reborn]

Yes, about the same amount of time. And since the caster started first, they finish first. The attack lands after the spell is finished.

That is your interpretation of the timing of actions. Since the action was readied, others (myself included obviously) feel the readied action should be completed first.

A caster can manage two spells a round plus movement with 1 action cantrips and a bonus action spell. Combat magic in 5e is fast.

Sure, a caster can cast a cantrip, cast a bonus spell, cast a reaction spell, and move. The reaction spell only "castable" on another creature's turn, in this case.

But a Fighter can attack up to nine times in six seconds as well as move 30 feet and use a reaction as well. Combat attacks in 5e is faster.

There is no "Interrupt Casting" action in 5e, nor is casting a 1 action spell subject to Concentration checks for suffering damage. An unprotected Wizard swimming through acid isn't required to make a Concentration check to cast a 1 action spell.

All true (sort of, as Counterspell is specifically interrupting a spell...), yet doesn't that sound ridiculous? Think about what you just wrote:

"An unprotected Wizard swimming through acid isn't required to make a Concentration check to cast a 1 action spell."

Still, I do see your point. You might argue why wouldn't the fighter swimming through acid have to make a check to attack? The DM might agree and say the fighter's attacks have disadvantage in that case. Likewise, a DM could easily rule a concentration check is required by a caster to cast a spell under such conditions. That is probably what our DM would do, and I would certainly agree it makes sense.

 

[UngeheuerLich]

It's pretty simple. "You can take your action right after the trigger finishes." If the trigger is someone casting a spell, you take your action after they cast the spell.

Nope it is not that easy. You can ready your attack on something visual like: "if the Mind flayer makes gestures with its hand and mutters words" That way you will attack before the spell is cast. If you trigger on "if the Mind flayer casts a spell, I would go with your interpretation"

 

[TaranTheWanderer]

This is where I don’t like to read the rules too precisely and This is where I like to use intent. Is the player trying to interrupt an action? Yes? Then I don’t ask for precise wording. The player wants to catch the caster in the midst of casting a spell. He times it, fakes his throw and as the caster pulls out a spell component, he throws the spear, knocking the sand out of the caster’s hand.

 

[MarkB]

Nope it is not that easy. You can ready your attack on something visual like: "if the Mind flayer makes gestures with its hand and mutters words" That way you will attack before the spell is cast. If you trigger on "if the Mind flayer casts a spell, I would go with your interpretation"

You're still acting after the triggering event "the Mind flayer makes gestures with its hand and mutters words" finishes, though.

 

[Torquar]

Still, I do see your point. You might argue why wouldn't the fighter swimming through acid have to make a check to attack? The DM might agree and say the fighter's attacks have disadvantage in that case. Likewise, a DM could easily rule a concentration check is required by a caster to cast a spell under such conditions. That is probably what our DM would do, and I would certainly agree it makes sense.

If you and your group want to make up house rules to penalize casters, go for it. RAW your readied attack isn't interrupting a 1 action spell in 5e.