What ways are there to disrupt spellcasting in 5e?

[Myth27]

So preparing an action to attack when the enemy cast doesn’t work anymore. Are there feats or abilities that let you do it? (Other than counterspell)

Edit: I would also be interested to know about any monsters/npc that can disrupt casting if you can think of any

[Unoriginal]

So preparing an action to attack when the enemy cast doesn’t work anymore. Are there feats or abilities that let you do it? (Other than counterspell)

If you mean "disrupt a spell that is currently being cast", then nope, there's none by RAW.

There is plenty of ways to make a spellcaster not able to cast, though. Like blocking their line of sight, blocking their hands, stopping them from talking, etc.

[Talionis]

Darkness can block line of sight. Silence stops spells with a verbal component. Anti Magic Field is a high level spell but does exactly what you want.

Mage Slayer feat is also useful. Also remember that at least half of all spells require concentration which can be broken with damage against a concentration check.

Interestingly a Shadow Monk has access to these spells and is Martial focused.

[Waazraath]

So preparing an action to attack when the enemy cast doesn’t work anymore. Are there feats or abilities that let you do it? (Other than counterspell)

Edit: I would also be interested to know about any monsters/npc that can disrupt casting if you can think of any

Grapple to prevent somatic / material components, maybe even verbal depending on DM?

As for monsters: the beholder's anti magic cone, of course, and afb, but I think it was the demi lich that has a legendary action (or lair action) that works as an antimagic field that targets 1 person.

[Dungeon-noob]

Hit them really, really hard. High damage means difficult concentration check. Giving them disadvantage on those first also really helps.

[Captain Bob]

If you're targeting a non-arcane caster that won't have the shield spell, magic missile is a good choice - three concentration checks for an auto-hit first level spell

ALSO - higher level arcane tricksters and monster hunter rangers have a few neat reactions that sort of do this

[Aquillion]

If you mean "disrupt a spell that is currently being cast", then nope, there's none by RAW.

There is plenty of ways to make a spellcaster not able to cast, though. Like blocking their line of sight, blocking their hands, stopping them from talking, etc.

I believe you can ready an action to take when someone starts casting a spell (possibly even a specific spell, if you can make the Arcana check to identify it.)

In that case you can use any of those methods to stop them, although it would normally require magic yourself. For example, you could ready an action to cast Silence when the enemy starts to cast a spell. When they do so, you could roll Arcana to determine the spell, then decide if you want to silence it or not. The poor-man's counterspell, essentially - doesn't require a roll for high-level spells, but requires you ready your action in advance and only works on spells with verbal components.

[Naanomi]

A monk’s stun is a pretty efficient disruption to spell casting

[Throne12]

Grapple to prevent somatic / material components, maybe even verbal depending on DM?

As for monsters: the beholder's anti magic cone, of course, and afb, but I think it was the demi lich that has a legendary action (or lair action) that works as an antimagic field that targets 1 person.

Grapple doesn't effect anything but movement.

[JoeJ]

I believe you can ready an action to take when someone starts casting a spell (possibly even a specific spell, if you can make the Arcana check to identify it.)

In that case you can use any of those methods to stop them, although it would normally require magic yourself. For example, you could ready an action to cast Silence when the enemy starts to cast a spell. When they do so, you could roll Arcana to determine the spell, then decide if you want to silence it or not. The poor-man's counterspell, essentially - doesn't require a roll for high-level spells, but requires you ready your action in advance and only works on spells with verbal components.

A readied action goes after the trigger, so it can't stop the spell from being cast. And you can't use Arcana to identify a spell and then take a readied action because you only have one reaction per round.

[Aquillion]

A readied action goes after the trigger, so it can't stop the spell from being cast. And you can't use Arcana to identify a spell and then take a readied action because you only have one reaction per round.

That's why you ready the action to go when they start casting the spell, rather than when they've cast it. Casting a spell takes time. (Note that the way readied spells work is that you cast it in advance, so you can easily outspeed their action with your reaction and unleash it in the sliver of time specified.)

You can absolutely interrupt other people's actions with your readied action like that as long as you specified what you were waiting for properly - otherwise the basic examples of eg. interrupting someone's movement wouldn't make sense ("yes, you readied an action to pull the lever when the cultist steps on the trapdoor, but it only goes off after their action, so they've already moved past it by the time you can react.")

And where does it say that using Arcana to identify a spell is a reaction? That would make it almost useless, since you wouldn't actually be able to do anything with the information you got (in particular, Arcana check + counterspell is pretty essential - without that, every single counterspell would have to be utterly blind.)

[Coffee_Dragon]

If you're targeting a non-arcane caster that won't have the shield spell, magic missile is a good choice - three concentration checks for an auto-hit first level spell

Has this been confirmed? The concentration rules specifically say you roll separate checks for damage from multiple sources, but a Magic Missile spell is a single source.

[Captain Bob]

https://twitter.com/jeremyecrawford/...401600?lang=en

Probably as definitive as it's going to get - each missile is considered a 'source of damage'. This would apply with scorching ray, or ice-knife etc. as well.

[JoeJ]

That's why you ready the action to go when they start casting the spell, rather than when they've cast it. Casting a spell takes time. (Note that the way readied spells work is that you cast it in advance, so you can easily outspeed their action with your reaction and unleash it in the sliver of time specified.)

I don't expect that a lot of DMs would allow that interpretation. Of course, the only DM who matters is the one at your table, so you should check with them.

And where does it say that using Arcana to identify a spell is a reaction? That would make it almost useless, since you wouldn't actually be able to do anything with the information you got (in particular, Arcana check + counterspell is pretty essential - without that, every single counterspell would have to be utterly blind.)

It's in XGtE, p. 85. You can use your reaction to identify a spell as it's being cast, or an action to identify one afterward. And yes, Counterspell is always cast blind unless the enemy spellcaster stupidly announces in advance spell what they're casting. (And even if they did that, could you trust them?)

[Tanarii]

And yes, Counterspell is always cast blind unless the enemy spellcaster stupidly announces in advance spell what they're casting. (And even if they did that, could you trust them?)

Consider the idea of a (probably BBEG's minion) caster yelling Fireball when it's casting a Fire Bolt stolen.

[JoeJ]

Consider the idea of a (probably BBEG's minion) caster yelling Fireball when it's casting a Fire Bolt stolen.

You really shouldn't announce your attacks in advance.

[Kane0]

Consider the idea of a (probably BBEG's minion) caster yelling Fireball when it's casting a Fire Bolt stolen.

Or just ‘BURN!’ Could be firebolt, burning hands, scorcher, scorching rays, flaming sphere, fireball, wall of fire...

[Unoriginal]

That's why you ready the action to go when they start casting the spell, rather than when they've cast it. Casting a spell takes time. (Note that the way readied spells work is that you cast it in advance, so you can easily outspeed their action with your reaction and unleash it in the sliver of time specified.)

You can absolutely interrupt other people's actions with your readied action like that as long as you specified what you were waiting for properly - otherwise the basic examples of eg. interrupting someone's movement wouldn't make sense ("yes, you readied an action to pull the lever when the cultist steps on the trapdoor, but it only goes off after their action, so they've already moved past it by the time you can react.")

And where does it say that using Arcana to identify a spell is a reaction? That would make it almost useless, since you wouldn't actually be able to do anything with the information you got (in particular, Arcana check + counterspell is pretty essential - without that, every single counterspell would have to be utterly blind.)

Trying to abuse semantics is not going to work. You can't Ready an action to interrupt a spell anymore that you can Ready an action to interrupt a sword attack.

The trigger is the Action in-game, not a part of the action.

As for the identification taking a Reaction, the rules are in the Xanathar's. You're supposed to Counterspell blind.

[Kane0]

Trying to abuse semantics is not going to work. You can't Ready an action to interrupt a spell anymore that you can Ready an action to interrupt a sword attack.

The trigger is the Action in-game, not a part of the action.

Citation needed

[Aquillion]

Trying to abuse semantics is not going to work. You can't Ready an action to interrupt a spell anymore that you can Ready an action to interrupt a sword attack.

Of course you can use a Ready action to interrupt a sword attack; I'm honestly shocked that anyone would suggest otherwise.

"I ready an action to do X moves to attack me" is, to me, one of the most basic usages of the Ready action. (Not capital-M moves, obviously.)

Again, one of the examples given in the book is "pull a lever while someone walks over a trapdoor." If you can't interrupt actions, that wouldn't make any sense (because you'd have to wait for them to finish their move, rendering the whole point of using a ready action for that moot.)

The trigger is the Action in-game, not a part of the action.

So if I said "I ready an action to pull this lever if someone walks over that trapdoor", you would say "fine, but it only works if they end their move on it, otherwise you can't interrupt them?"

The game isn't a computer program; words mean what they mean in plain English. Nothing in the Ready Action rules implies that you have to key it to a capital-A action. All it cares about is a "perceivable circumstance". And the example it gives specifically has you cutting into an enemy's movement. Here's what it says:

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. Examples include "If the cultist steps on the trapdoor, I'll pull the lever that opens it," and "If the goblin steps next to me, I move away."

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.

No limits like what you're saying on the "perceivable circumstance." DMs might reasonably object if you try to slice time too thinly to allow yourself time to react, but that isn't a problem with the examples given.

The whole point of the Ready Action (as it says) is to get the jump on your foe. Of course you can ready an action to respond to someone who's about to attack you.

I don't expect that a lot of DMs would allow that interpretation.

If they want to nerf the ready action, that's their call, but by my reading, "I ready an action to do [X] if someone begins to [Y]" (or halfway through Y or whatever) is the main purpose of the ready action - it allows you to cut in at key moments in ways that wouldn't otherwise be possible, at the cost of delaying your action, making it contingent on what happens, and possibly wasting it. The "you go after the trigger" wording just establishes that you need to have some sort of percievable trigger to react to and can't psychically act before you had any reason to think you should (ie. you can pull the lever as soon as you see someone, but you can't use that to pull the lever before someone steps into view.)

I think the vast majority of DMs would allow, it, though? It's clearly both RAW and RAI, and it isn't exactly powerful enough to require some sort of "you can only react to discrete capital-A Actions" ruling. Especially given that, again, your interpretation would make it mostly impossible to do the Ready Action laid out as an example.

Like, I'll be honest, most of the objections you and Unoriginal are raising seem baffling to me - I can neither understand how you could possibly interpret the Ready Action rules that way, nor why you would want to. The whole point of a Ready Action is to let you act just in time - if you had to specify an entire capital-A action as a trigger (and, therefore, go after that action was totally complete), you wouldn't be able to do much with it at all and would lose out on most of the creativity or reward for anticipating your enemies' actions that it offers.

Breaking out of the limits of the Action system to try and pull something (that you hope is) clever is the entire point.

[Rukelnikov]

Of course you can use a Ready action to interrupt a sword attack; I'm honestly shocked that anyone would suggest otherwise.

"I ready an action to do X moves to attack me" is, to me, one of the most basic usages of the Ready action. (Not capital-M moves, obviously.)

Of course, so much so, that the game already has such reactions :S Like Light Cleric's Warding Flare, a GOOLock's Entropic Ward, or the Protection Style.

[ProsecutorGodot]

Of course you can use a Ready action to interrupt a sword attack; I'm honestly shocked that anyone would suggest otherwise.

The issue with this logic is that both the examples given are related to using an enemies movement as the trigger. Movement is incremental and triggering a lever after they've stepped onto a trapdoor follows all rules for Ready Action.

If your trigger is an attack or spellcast being made though, these involve a defined process where "after the trigger" is only met once the attack is fully resolved or the spell has been cast (unless the spell has a casting time longer than 1 action, but that's not relevant here).

It's not possible to interrupt an action, you can only respond to it.

[JoeJ]

If they want to nerf the ready action, that's their call,

It's not a house rule, it's a ruling. If your DM rules otherwise, then that's how it will work at that table.

Like, I'll be honest, most of the objections you and Unoriginal are raising seem baffling to me - I can neither understand how you could possibly interpret the Ready Action rules that way, nor why you would want to. The whole point of a Ready Action is to let you act just in time - if you had to specify an entire capital-A action as a trigger (and, therefore, go after that action was totally complete), you wouldn't be able to do much with it at all and would lose out on most of the creativity or reward for anticipating your enemies' actions that it offers.

The rule is that you take your readied action right after the trigger finishes, not right after it starts. That's the RAW.

[Waazraath]

Grapple doesn't effect anything but movement.

Yeah, I know, but it is also an opposed athletics check, and skill rules are described in a notoriously limited way. What you can do exactly is up to the table conventions and DM, and I can imagine quite some would allow an opposed athletics when grappling to restrain a targets arms and / or prevent speaking.

[Rukelnikov]

The issue with this logic is that both the examples given are related to using an enemies movement as the trigger. Movement is incremental and triggering a lever after they've stepped onto a trapdoor follows all rules for Ready Action.

If your trigger is an attack or spellcast being made though, these involve a defined process where "after the trigger" is only met once the attack is fully resolved or the spell has been cast (unless the spell has a casting time longer than 1 action, but that's not relevant here).

It's not possible to interrupt an action, you can only respond to it.

There are examples of it happening in the PHB already (Light Cleric's Warding Flare, a GOOLock's Entropic Ward, or the Protection Style). Such a reaction goes after the attack has started and before it is resolved.

The rule is that you take your readied action right after the trigger finishes, not right after it starts. That's the RAW.

Exactly, if the trigger is "when he steps on the plate", once he sets foot on it the trigger has been completed.

Similarly, if the triggers is "when he starts casting", the trigger is fulfilled when he started it.

It would be different if the trigger was "when the cleric casts bless I shoot", in that case the trigger would not be completed until the spell has finished being cast successfully.

[Unoriginal]

Please, could you tell us when the "X foe starts casting a spell" trigger finishes?

[ProsecutorGodot]

There are examples of it happening in the PHB already (Light Cleric's Warding Flare, a GOOLock's Entropic Ward, or the Protection Style). Such a reaction goes after the attack has started and before it is resolved.

Those are exceptions, and they don't interrupt the trigger (in the sense of preventing it from happening) they change the outcome.

Please, could you tell us when the "X foe starts casting a spell" trigger finishes?

This is reminding me of when Crawford said "There is no taking the attack action, the attack just happens"

Seems relevant in the sense that there isn't an intent for such a trigger to exist.

[JoeJ]

Similarly, if the triggers is "when he starts casting", the trigger is fulfilled when he started it.

The trigger has to finish, not just start.

[TheUser]

So preparing an action to attack when the enemy cast doesn’t work anymore. Are there feats or abilities that let you do it? (Other than counterspell)

Gonna need a citation of some kind here.

The fantasy trope of a caster having a crossbow bolt plunge into his neck/hand/chest as he begins casting a spell only to be stifled by the trauma or have their intricate verbal/somatic components disrupted adequately is pretty common in medieval fantasy.

Even the idea of a guy stuffing his hand into the face of a mage before he finished casting a spell has been used. It's definitely a trope in these types of stories to say the least.

Even in older editions this has been a widely used mechanic so I need some definitive RAW support or at the very least some Sage Advice(*shudder*).

Oh and just to quash any doubts about this ridiculous notion that a caster gets to finish casting before you can interrupt with a readied action. If the trigger is "they start casting a spell" once they have started the trigger is resolved and your action goes off. They need not finish casting. There is loads of reactions that already function off of interrupting an action before it completes (counterspell being the most appropriate example; which literally describes using a reaction to interrupt a spell).

Spoiler: Counter Spell

Show

3rd-level abjuration

Casting Time: 1 reaction, which you take when you see a creature within 60 feet of you casting a spell.

Range: 60 feet

Components: S

Duration: Instantaneous

You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell of 3rd level or lower, its spell fails and has no effect. If it is casting a spell of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell’s level. On a success, the creature’s spell fails and has no effect.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the interrupted spell has no effect if its level is less than or equal to the level of the spell slot you used.

[ProsecutorGodot]

Gonna need a citation of some kind here.

The fantasy trope of a caster having a crossbow bolt plunge into his neck/hand/chest as he begins casting a spell only to be stifled by the trauma or have their intricate verbal/somatic components disrupted adequately is pretty common in medieval fantasy.

Even the idea of a guy stuffing his hand into the face of a mage before he finished casting a spell has been used. It's definitely a trope in these types of stories to say the least.

Even in older editions this has been a widely used mechanic so I need some definitive RAW support or at the very least some Sage Advice(*shudder*).

Oh and just to quash any doubts about this ridiculous notion that a caster gets to finish casting before you can interrupt with a readied action. If the trigger is "they start casting a spell" once they have started the trigger is resolved and your action goes off. They need not finish casting. There is loads of reactions that already function off of interrupting an action before it completes (counterspell being the most appropriate example; which literally describes using a reaction to interrupt a spell).

Spoiler: Counter Spell

Show

3rd-level abjuration

Casting Time: 1 reaction, which you take when you see a creature within 60 feet of you casting a spell.

Range: 60 feet

Components: S

Duration: Instantaneous

You attempt to interrupt a creature in the process of casting a spell. If the creature is casting a spell of 3rd level or lower, its spell fails and has no effect. If it is casting a spell of 4th level or higher, make an ability check using your spellcasting ability. The DC equals 10 + the spell’s level. On a success, the creature’s spell fails and has no effect.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the interrupted spell has no effect if its level is less than or equal to the level of the spell slot you used.

I'm not sure that citing the only reaction that explicitly allows you to interrupt a spell being cast opens the door to an arrow serving the same function.

It's an exception, a very very specific one at that.