[5E] Interrupting a Spellcaster via Ready Action

UngeheuerLich · Mar 2, 2019

Just for information from the SRD

Ready

Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn, which lets you act using your reaction before the start of your next turn.
First, you decide what perceivable circumstance will trigger your reaction. Then, you choose the action you will take in response to that trigger, or you choose to move up to your speed in response to it.

In no way the trigger has to be an action. It is just not there. So anyone saying the spellcasting is finished is wrong here.

Nickolaidas · Mar 2, 2019

UngeheuerLich said:
Just for information from the SRD

In no way the trigger has to be an action. It is just not there. So anyone saying the spellcasting is finished is wrong here.

The part the 'naysayers' are referring to is right after what you've cited.

"When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger."

It's the word 'finishes' which creates this whole debate. When the trigger is 'the second I see him mumbling and waving his hands', some players believe that 'trigger finishes' means 'finishes mumbling and waving his hands', which probably means 'finished casting a spell'.

Torquar · Mar 2, 2019

UngeheuerLich said:
Edit: and no that is no house rule. That is the rule as in the PHB. The trigger can be anything you can perceive, not an action. Move fingers is something you perceive before the spellcasting is finished. Actually I would allow the spellcaster a sleight of habd check to conceal such a movement to still try and cast the spell. But when you fail, the trigger is fulfilled, but that would be a ruling, not a rule.

But you don't get to perform your readied action until the trigger action is completed. Guess what happens when the caster finishes moving his fingers?

UngeheuerLich · Mar 2, 2019

Torquar said:
But you don't get to perform your readied action until the trigger action is completed. Guess what happens when the caster finishes moving his fingers?

The problem is: the trigger is not the spellcasting action. In no way is it stated that the trigger is an action. To quote the relevant part:

When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger. Remember that you can take only one reaction per round.

It even says: when the trigger finishes. Not the triggering action or action. Just trigger. Which is as quoted above is a perceivable circumstance.
So guess what happens after you move a finger. You get short. If you live through this you can move your finger further and finish casting the spell.

UngeheuerLich · Mar 2, 2019

Nickolaidas said:
The part the 'naysayers' are referring to is right after what you've cited.

"When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger."

It's the word 'finishes' which creates this whole debate. When the trigger is 'the second I see him mumbling and waving his hands', some players believe that 'trigger finishes' means 'finishes mumbling and waving his hands', which probably means 'finished casting a spell'.

Even this part does not speak of an action. It is just a trigger. And a clever trigger is not "cast a spell" which you only perceive when it is finished but "moves a finger an inch" or "says a word" which usually is not enough to get off a spell, but might accidently make you shoot even if the enemy does not actually cast a spell. The naysayers are just wrong here.

Torquar · Mar 2, 2019

UngeheuerLich said:
Even this part does not speak of an action. It is just a trigger. And a clever trigger is not "cast a spell" which you only perceive when it is finished but "moves a finger an inch" or "says a word" which usually is not enough to get off a spell, but might accidently make you shoot even if the enemy does not actually cast a spell. The naysayers are just wrong here.

If you're going to set "Moves a finger" or Speaks a word" as your trigger, you might as well just attack. It's extremely unlikely that the caster is going to be silent and immobile until he starts casting...

UngeheuerLich · Mar 2, 2019

Torquar said:
If you're going to set "Moves a finger" or Speaks a word" as your trigger, you might as well just attack. It's extremely unlikely that the caster is going to be silent and immobile until he starts casting...

I told you what circumstances would be appropriate for the readied action: subduing a spellcaster at range. In melee I would just bludgeon him unconscious. But at range I might shout "stop. Don't move or do something stupid or I'll shoot." And ready appropriately. In no way should this be a standard procedure in combat.

Swarmkeeper · Mar 2, 2019

Torquar said:
If you're going to set "Moves a finger" or Speaks a word" as your trigger, you might as well just attack. It's extremely unlikely that the caster is going to be silent and immobile until he starts casting...

"Don't move or I'll shoot... er, I mean... or I'll throw my spear at you!" Perfectly reasonable course of action for a PC to take.

MarkB · Mar 3, 2019

DM Dave1 said:
Ah, I see: you feel a movement trigger is different than an action trigger. That's fine, I suppose. But the trigger can be anything the player specifies.

Attempting to cast a spell is moving a hand, or grabbing a spell component, or starting to speak magic words. A completely acceptable trigger is: "if the Flayer attempts to cast a spell, I throw my spear." Perhaps you prefer more nuanced wording and want the fighter to specify: "if the Flayer starts to cast a spell, I throw my spear."

All of those are acceptable wordings. And in all cases, you'd attack after the spell was cast, because the trigger is the spell being cast.

A similar trigger might be: "If the Grimlock raises its club to attack the wizard, I throw my spear at it." The Grimlock is attempting to attack, yes? It is starting to attack, right? Why should the fighter have to wait for the club to fall before throwing the spear that is already at the Ready?

Because that's what the rules say. It's even the specific case used in the Sage Advice quote cited earlier in the thread. You are readying an attack in the event of the Grimlock attacking the wizard, and therefore your reaction occurs after that event finishes. Otherwise why would they have bothered including that line in the rules?

Or perhaps you're looking for super-specificity: "if the Flayer moves its hand or makes a noise, I throw my spear at it." Acceptable?

Perfectly acceptable. And your readied action will be triggered immediately, because the Mind Flayer is neither standing as still as a statue nor attempting to be completely silent.

As a DM, I'm looking for the spirit of what the player is trying to have their PC do. Any of those Ready wordings are fine to me. We're not playing "Mother-May-I" at our table. If that's the style of play at your table and everyone is on board and having fun with it, carry on.

The difference is, I'm not looking for a specific clever wording or special circumstance that will allow this, because I'm confident that the reason the rules were worded as they are is in order to not allow this. There is no way to use a Readied attack to disrupt the casting of a spell, so no amount of special phrasing will accomplish it.

Ristamar · Mar 3, 2019

The 5e equivalent of "don't move or I'll shoot" is the initiative roll.

[5E] Interrupting a Spellcaster via Ready Action

UngeheuerLich

Legend

Nickolaidas

Explorer

Torquar

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UngeheuerLich

Legend

UngeheuerLich

Legend

Torquar

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UngeheuerLich

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Swarmkeeper

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MarkB

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Ristamar

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