Recognize spell being cast / counterspell / dispel magic

[Tanarii]

Based on a post I made in another thread:
Is recognizing what spell is being cast even possible? This is important for various reasons. But the first one that jumps to mind is Counterspell. The way Counterspell is worded makes me think that you're guessing what spell slot to use to counter the enemies spell being cast, and don't actually know. And even after it's been cast, can you tell what was cast in order to figure out what level of Dispel Magic to use, or is that a guess too?

Without a tangible affect, or a specific material component that is unique to the spell and seen, how would you know what spell was cast? Or is being cast while it's being cast? There's nothing to indicate that a given spell requires specific V or S components that are unique to the spell *and* common to every caster of the spell. There's nothing that even says a given caster casting a given spell uses the same S component when casting in conjunction with a focus that he uses in conjunction with an M component. And while Arcane allows you to recall lore about spells, there's nothing to indicate it lets you figure out which spell is being cast.

Reading Detect Magic, it seems he best you can do is know something is magical, and what school it is. Or see a obvious and clear affect in place (Wall of Fire/Stone/Force). My first thought was its ask-your-DM territory, but I'm leaning more towards it being "no you can't".

So I'm wondering if anyone has found anything in the books that seems to indicate one way or the other. Especially since it has various game ramifications in terms of Counterspell / Dispel Magic and probably other things I haven't thought of yet.

[Douche]

I'm not sure I understand your question... but I also don't really understand Counterspell, myself. Since it's a reaction, does that mean that you can use it at any time when an enemy is casting a spell? Or do you have to prepare it in advance, sacrificing your action to prepare the counterspell in hopes of your enemy using a spell that turn?

"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."

So, is your question "How can I tell what spell the enemy is using to know whether it's worth countering"?

Edit: also, you don't need to know the spell or it's level to counter it. It just has a DC if you're using Counterspell as 3rd level. You can bypass the DC by using a higher level spell slot

[Safety Sword]

You make a snap decision to counter a spell.

You don't need to know what it is. You just do it.

And let's be honest, it's Fireball. It's always Fireball

[Slipperychicken]

I'm not sure I understand your question... but I also don't really understand Counterspell, myself. Since it's a reaction, does that mean that you can use it at any time when an enemy is casting a spell? Or do you have to prepare it in advance, sacrificing your action to prepare the counterspell in hopes of your enemy using a spell that turn?


Yes. The only action which needs to be taken is a reaction to cast it. Of course, you need to be able to use your reaction, which may not be possible in some cases.



So I'm wondering if anyone has found anything in the books that seems to indicate one way or the other. Especially since it has various game ramifications in terms of Counterspell / Dispel Magic and probably other things I haven't thought of yet.

In 3rd edition, anyone who observed a spell's verbal or somatic components would roll Spellcraft (http://www.d20srd.org/srd/skills/spellcraft.htm) (a skill analogous to Arcana) to identify the spell as it was being cast. As far as lore is concerned, if not 5e RAW, that implies that verbal and somatic components are unique to the spell being cast. If you look closely, the skill also allowed people to identify spells already place, but only if they are aware of the spell, which usually required Detect Magic or similar.

As a result of that precedent, I think it's appropriate to give Arcana checks to identify spells as they are being cast. For DCs, a decent guideline would be 10+spell level.

[Goober4473]

I'd allow an Intelligence (Arcana) check to identify a weird spell by verbal components, somatic movements of the caster, etc., or just tell the players if it's something common or a spell one of them knows. Often I find what happens is, I begin describing the effect of a spell, then a player is like, "wait I have counterspell!" and I'll let them go ahead, so that can be another way to identify a spell: the early onset of its effects.

But do note that you don't need to know what spell is being cast in order to cast Counterspell. It can be helpful to know what slow you need to expend in order to auto-cancel the spell, but worst case, you either spend a higher slot than you needed, or you have to pass a check to be successful. Not too bad.

[Theodoxus]

This debate again?

Yes, there was a Spellcraft check in 3.X. No, there isn't a Spellcraft check in 5th. This is deliberate.

No, there's no RAW way to know what spell is being cast. This is deliberate.

Yes, that means if an enemy is casting as spell, you have to decide whether you think it's worth blowing a 3rd level (or higher) slot on countering it. Given that's its an enemy casting the spell, in combat, you've a pretty good chance of it not being harmless (either it will be detrimental to you, or beneficial to them). This is deliberate.

You can certainly houserule anything you'd like to bring more skill usage to the game - one example is Arcana for Bard/Sorc/Warlock/Wiz spells, Religion for Cleric and Paladin spells and Nature for Druid and Ranger spells. DC = 8 + Casting mod + spell level. This has the added benefit of making Int more useful, and those three skills more prevalent in games.

However, skills are actions when used in combat. Allowing someone to use Arcana (or Nature/Religion) as part of a reaction to cast Counterspell is definitely stretching the RAW use of skills. I caution against doing this - but it's your game :smallbiggrin:

[Demonic Spoon]

However, skills are actions when used in combat.

I am virtually certain this is incorrect unless you can cite a general rule somewhere?

[Fwiffo86]

Without a tangible affect, or a specific material component that is unique to the spell and seen, how would you know what spell was cast? Or is being cast while it's being cast? There's nothing to indicate that a given spell requires specific V or S components that are unique to the spell *and* common to every caster of the spell. There's nothing that even says a given caster casting a given spell uses the same S component when casting in conjunction with a focus that he uses in conjunction with an M component. And while Arcane allows you to recall lore about spells, there's nothing to indicate it lets you figure out which spell is being cast.

For years we (my table and crew) have gone with the actual VSM components of the same spell are NOT the same from spell book to spell book, wizard to wizard, Priest to priest, or arcane to divine caster. And given you had to cast Read Magic to decipher a spell in a recovered book or scroll, I would easily argue that our interpretation was completely correct.

There was no way to tell what spell was being cast UNTIL 3rd. The counterspell mechanics in 3rd made sense, if you assume that everyone and everything casts fireball in the exact same way (which given that rise of sorcs and monsters that cast naturally without memorization or preparation NEVER made sense to me), uses the exact same hand motions, and chants the exact same words. Our table never found this as representative of the way previous editions represented magic, and chose to ignore it.

In 5e, we again find that there is no way to identify a spell as it is being cast without adding some homebrew. You don't actually need to know anyway. Counterspell and dispel magic completely negate the magic if they match or exceed spell level. There is no roll. The only roll is if you sling a counterspell (3rd slot) at a 5th slot spell or such. Even then, there is a reasonable chance you'll counter it anyway. No more needing to cast the same spell to instant counter, or with the feat use the same school. Its far easier, AND keeps the spellcasting "method (for lack of a better term)" completely fluid.

It is nice to know that you can just flat out counterspell PWK, or Wish, or what have you. Best use of a 9th slot if you ask me.

[Mjolnirbear]

I'd say not per RAW.

The rules support purely cosmetic changes, such as magic missile taking the form of flaming skulls. A cleric's somatic components are, thematically at least, prayer, which would be completely illogical from an arcane caster (except maybe the warlock). A wizard must gesture somatic components, while a sorcerer might metamagic it away and a paladin might use his shield that is emblazoned with a holy symbol.

This implies incredible individual variation between casters.

I could agree with a houserule that allowed you to identify a spell you already know that has a specific material component. It's no big stretch that if you can cast Find Familiar that you recognize that anyone casting a spell requiring an expensive brazier is probably casting the same spell.

I can even agree with a more permissive version of the same rule that allows a check as long as the spell is able to be prepared by you, even if there is no expensive material component.

But i consider it a feature, not a bug, that you don't RAW get to know what you're dispelling or countering. It's safe to assume any spell an enemy is casting is bad news for you. It is also an intelligent tactic to draw out a counterspell by casting a useless spell, but even if the enemy does this, your counterspell is not wasted: it achieved the desired objective by NOT LETTING HIM HURT YOU WITH HIS SPELLS. If you stopped him by countering his Finger of Death or stopped him by causing him to cast Minir Illusion to draw out your counterspell, either way his round was ineffectual, and your party has one more round to kill him with.

[Skeller]

So I know that most people think that the players never having any idea what is going on or what is being cast is a feature not a bug but I prefer having players have at least a chance of knowing what is happening. I just use Knowledge Arcana/Religion/Nature at 10+spell level. I would pretty much suggest going with whatever feels best to you and your group however. In the end the only "wrong" way to play D&D is the way that you have no fun doing.

[Slipperychicken]

For years we (my table and crew) have gone with the actual VSM components of the same spell are NOT the same from spell book to spell book, wizard to wizard, Priest to priest, or arcane to divine caster. And given you had to cast Read Magic to decipher a spell in a recovered book or scroll, I would easily argue that our interpretation was completely correct.
This does not preclude the chance of someone identifying them, however.

Someone learned in magic would have learned many of the ways each spell is cast. There might be hundred ways to cast a fireball, but many would be recorded and taught. There are quite a few magical researchers going around in the dnd universe; it seems odd that their work would be entirely for naught. Or perhaps there are some patterns or motifs which can give away a spell's identity. All these sorts of things would be included in the arcana skill.

[bardo]

I second the notion that Counterspell is most likely intended as a "blind" reaction.

I don't see a problem with house-ruling that it's possible to tell which spell is being cast (nor a real benefit to adding this dimension to the game). Just wanted to add that my personal view that it's better accomplished with a contest than with a plain ability check vs DC.

In a world where it is possible to tell which spell is being cast, all casters will be trained in obfuscated casting. Clench Ms in a tight fist, keep Ss under your cloak, turn your head and cover your mouth for the Vs. Like that awful movies says: "Hide your strikes from your opponent and you'll more easily strike his hide". Fighters are trained to hide their true intentions from their opponents, spell casters would be trained to hide their spells. Nothing special required on part of the caster, obfuscated casting would be the norm.

It could be Intelligence (arcane/nature/religion) check to identify a spell Vs. spell casting ability check to cast it without giving clues to what the spell is. It could even be Wisdom (insight) check vs Charisma (deception) check.

Bardo.

[Malifice]

Is recognizing what spell is being cast even possible?

Only if youre a Kobold and its a PC casting minor illusion.

:smallwink:

[Tanarii]

Okay, so it sounds like the consensus (so far) is no, but that some folks advocate using arcana or the knowledge skills to an Int check to get that info. Anyone ever seen a Jc tweet or anything official on it?


If you look closely, the skill also allowed people to identify spells already place, but only if they are aware of the spell, which usually required Detect Magic or similar. Reference? It's not under the 5e Arcana skill, I just re-read it. Or are you talking about 3e? Because that's a different edition, it's rules are not relevant to 5e, nor do I have the books any longer. Besides I go back to 1e/BECMI, and I can't recall spells being cast being identifiable in 1e or 2e.


Only if youre a Kobold and its a PC casting minor illusion.

:smallwink:hahaha well done. :)

[Slipperychicken]

Reference? It's not under the 5e Arcana skill, I just re-read it. Or are you talking about 3e? Because that's a different edition, it's rules are not relevant to 5e, nor do I have the books any longer. Besides I go back to 1e/BECMI, and I can't recall spells being cast being identifiable in 1e or 2e.


Please carefully re-read the entire paragraph that sentence came from. I was explicitly referring to a similar skill from 3rd edition. I did that to make a point about D&D lore, and not the rules-as-written in 5th edition. I even included a link to the 3rd edition rule.

I am trying to illustrate that the idea (of spells being identifiable by their distinctive gestures and vocalizations) has precedent in prior editions of D&D. Where the current edition's rules might be unclear, looking to a previous edition for guidance may be helpful.

[Tanarii]

Please carefully re-read the entire paragraph that sentence came from. I was explicitly referring to a similar skill from 3rd edition. I did that to make a point about D&D lore, and not the rules-as-written in 5th edition. I even included a link to the 3rd edition rule.

I am trying to illustrate that the idea (of spells being identifiable by their distinctive gestures and vocalizations) has precedent in prior editions of D&D. Where the current edition's rules might be unclear, looking to a previous edition for guidance may be helpful.
Yes, but then and now were trying to tie in that prior edition thing as being somehow relevant to 5e. Which is why I was looking for what you were talking about in the 5e Aracana skill ... that would be relevant.

3e rules aren't particularly relevant to this edition. But even if it was, the fact the 5e skill doesn't correspond is more telling that what the 3e skills says by itself. And even if it was, 3e isn't the entirety of d&d lore for establishing precedent.

[AeonsShadow]

As is my limited understanding of the spell, COUNTERSPELL isn't actually targeting THE SPELL BEING CAST. More like it's targeting THE FUEL SOURCE. If the flow of raw magical energy being manipulated to fuel the spell is suddenly cut, then the spell fails, not having the power for it's intended effect, right?

Dispel magic probably works something similar but is more focused on dispersing magical effects already put in place and long since active.

[coredump]

However, skills are actions when used in combat.
There is nothing in the PHB that makes this a general rule. And there are many situations that would make a rule such as this seem very foolish.


As for the OP... it is an area completely uncovered by the rules...they left it completely to DM adjudication.

Around here we let you automatically know any spell on your spell list and of a level that you could cast/ (So at level 7, all spells on your list of level 4 an below)
If its not on your list and/or a higher level...then it takes a skill check.

But to be honest... its all theory so far...not alot of counterspell folks around.

[djreynolds]

What about versus powers and auras? Does it defeat anything requiring a save? You can dispel a fireball, but not dragon breath right?

[HarrisonF]

What about versus powers and auras? Does it defeat anything requiring a save? You can dispel a fireball, but not dragon breath right?

Right, Dispel and Counterspell both work only on spells, not abilities unless they produce a spell. It does lead to some very weird rulings, but that is how it works.

As far as identifying for counterspell, the way we play it is that if the spell being cast is on your class spell list and is of a level you can cast, then you know what it is, both the power and the specific spell name. If not, then you don't know it. I highly recommend against using a roll to identify as it really goes against the streamlining that 5ed put into combat.

After it is cast, you can only tell what an existing effect is by the Identify spell. The Identify spell can already identify spells on objects and creatures. It isn't much of a stretch to add it can also do other generic magical effects.

[Sredni Vashtar]

There is nothing in the PHB that makes this a general rule. And there are many situations that would make a rule such as this seem very foolish.

Such as determining whether or not you know something. You either know what spell it is or you don't. That's the Int (Arcana) roll.

[Tanarii]

Such as determining whether or not you know something. You either know what spell it is or you don't. That's the Int (Arcana) roll.
It doesn't apply to identifying spells being cast, by the default RAW. It allows you to recall lore about spells.

Obviously any DM can call for any skill check they want. Normally I'd be all over permissiveness for that kind of thing. But this is a potentially huge factor in how spell casting actually plays out in game at multiple levels.

To all: I'm looking for something at least semi-official for AL play reasons. So far, I'm having to take the rules silence of the matter as: No, officially you can't identify spells being cast.

[Mad_Saulot]

The type of spell isnt important, the counterspell attacks the weaving of the spell, not the spell itself.

As far as identifying spells I'd rule that you can recognise any spell you know/in your spellbook, but you dont literally know all spells of your level or below because characters in my games dont run around with a meta version of the players handbook in their heads. It requires the appropriate skill roll, arcana to identify arcane spells, religion to identify divine spells (nature doesnt help with any kind of spell identification).

So for counterspell its fairly simple, if you cast counterspell at 3rd level if the enemy is casting a 3rd level spell or lower you auto-counter it, if its higher level you need to roll. The same caster could decide to use a higher level slot to cast it in order to counter a higher level spell automatically but this is kinda like a blind raise, something you might do if you suspect the enemy is casting at higher level, but you wont know until after the spell is cast. This means that it becomes a tactical decision. With a certain level of risk. This also rewards preparation, if you rush into a fight with a powerful warlock then you are less likely to win than if you do some recon/intel gathering first, if a player seeks to garther intel on his enemy before facing him I might provide details of his spell list, based on what spells the villain has used against his victims, this means investigating an enemy before facing him can prove invaluable.

If in doubt just cast as 3rd level, even if it was disintegrate you still have a good chance of making it fizzle.

[Pex]

You make a snap decision to counter a spell.

You don't need to know what it is. You just do it.

And let's be honest, it's Fireball. It's always Fireball

Some players may want to be more prudent. If the enemy spellcaster is casting Stinking Cloud the player may want to Counter it, but if the spell was Flaming Sphere instead the player may think the party can just deal with that and save his spell slot for later. An enemy spellcaster casting a spell is always harmful, but there are degrees of harmfulness.

[Fwiffo86]

Some players may want to be more prudent. If the enemy spellcaster is casting Stinking Cloud the player may want to Counter it, but if the spell was Flaming Sphere instead the player may think the party can just deal with that and save his spell slot for later. An enemy spellcaster casting a spell is always harmful, but there are degrees of harmfulness.

Agree with the Degrees of harmful. But I don't think there is any precedent for "needing" to know. You either stop them or don't. Its your risk for preventing magic from hitting the field. There is no "need" for players to know what spell is being cast. Really there isn't. There is no mechanic that operates of it, and no skill for identifying it.

Traditionally it has been this way more often than not.

[Demonic Spoon]

I would lean towards not allowing it purely on the basis that counterspell is already very strong and allowing someone to make a perfectly informed decision about their counterspell (what level slot they need to use to guarantee success, what effect they're preventing if they use the slot) takes the spell from "very good" to "mandatory".


Allowing someone to know a spell being cast also has other interactions with balance. For example, illusions would no longer be usable in combat, since any opponent could make an Arcana check to learn that the spell being cast was an illusion and thus whatever springs from it is not real.

[Vogonjeltz]

Please carefully re-read the entire paragraph that sentence came from. I was explicitly referring to a similar skill from 3rd edition. I did that to make a point about D&D lore, and not the rules-as-written in 5th edition. I even included a link to the 3rd edition rule.

I am trying to illustrate that the idea (of spells being identifiable by their distinctive gestures and vocalizations) has precedent in prior editions of D&D. Where the current edition's rules might be unclear, looking to a previous edition for guidance may be helpful.

PHB 203, under Components, Verbal: "Most spells require the chanting of mystic words. The words themselves aren't the source of the spell's power; rather the particular combination of sounds, with specific pitch and resonance, sets the threads of magic in motion."

So it looks like it's not the words that count per se, it's how the character is saying whatever words they say.

I'd be inclined to say the only way a character could know what a creature is casting is if they had seen the creature cast the same spell. The Keen Mind feat would be pretty handy in this regard for the ability to recall seeing/hearing things within the month.

[LordBlades]

I would lean towards not allowing it purely on the basis that counterspell is already very strong and allowing someone to make a perfectly informed decision about their counterspell (what level slot they need to use to guarantee success, what effect they're preventing if they use the slot) takes the spell from "very good" to "mandatory".


On the other hand, this would move counterspell from 'I can counterspell something, I'll never know what it was, let's just hope the slot wasn't wasted. Meh'
to 'I now have to make an informed tactical decision if counterspelling this particular spell is worth a spell slot and my reaction'. I find the latter farm more exciting than the former.

IMO anything that gives the players (as opposed to mere chance) more agency regarding the outcome of a situation is a good thing.

[Pex]

I would lean towards not allowing it purely on the basis that counterspell is already very strong and allowing someone to make a perfectly informed decision about their counterspell (what level slot they need to use to guarantee success, what effect they're preventing if they use the slot) takes the spell from "very good" to "mandatory".


Allowing someone to know a spell being cast also has other interactions with balance. For example, illusions would no longer be usable in combat, since any opponent could make an Arcana check to learn that the spell being cast was an illusion and thus whatever springs from it is not real.

"Mandatory" is subjective. To cast the spell is still to use up a spell slot not used for something else later. It's not for the DM to decide how a player uses his spells, barring the obligatory mention of making the game not function such as a Simulacrum Army from Wishing. A player countering a known spell is not one of those making the game not function things.

[JoeJ]

"Mandatory" is subjective. To cast the spell is still to use up a spell slot not used for something else later. It's not for the DM to decide how a player uses his spells, barring the obligatory mention of making the game not function such as a Simulacrum Army from Wishing. A player countering a known spell is not one of those making the game not function things.

Countering a known spell doesn't break the game in itself, but allowing a PC to identify illusions with only a skill roll that doesn't even require an action has a significant effect. And turning it around to allow NPCs to do that to illusion spells cast by a PC makes certain character concepts so bad as to be essentially unplayable.

[Sredni Vashtar]

It doesn't apply to identifying spells being cast, by the default RAW. It allows you to recall lore about spells.

Obviously. I was more talking to the use of what is basically a knowledge check requiring an action while in combat. Regardless of the RAW ruling regarding Counterspell (personally, I'd allow an Arcana check to identify the spell, but that's also a personal ruling and not RAW), I still feel that answering the question of "do I know this?" shouldn't require the better part of six seconds.


Countering a known spell doesn't break the game in itself, but allowing a PC to identify illusions with only a skill roll that doesn't even require an action has a significant effect. And turning it around to allow NPCs to do that to illusion spells cast by a PC makes certain character concepts so bad as to be essentially unplayable.

"Identify" illusions how? Identifying as in recognizing something as an illusion? Isn't that an Intelligence check with the prerequisite of having a reason to disbelieve it? Or are we talking about identifying the spell that created the known and recognized illusion? That sounds like a RAW interpretation of the Arcana skill to me.

[Demonic Spoon]

"Identify" illusions how? Identifying as in recognizing something as an illusion? Isn't that an Intelligence check with the prerequisite of having a reason to disbelieve it? Or are we talking about identifying the spell that created the known and recognized illusion? That sounds like a RAW interpretation of the Arcana skill to me.

If a PC tries to cast an illusion in combat, and the enemies all get arcana checks to recognize the spell, then the enemies know that it's an illusion, thus making it pretty close to worthless.

[coredump]

To all: I'm looking for something at least semi-official for AL play reasons. So far, I'm having to take the rules silence of the matter as: No, officially you can't identify spells being cast.
That isn't how AL is set up. This is an area with no explicit rules, thus you will need to ask your DM how he/she plans on adjudicating it.

[Pex]

If a PC tries to cast an illusion in combat, and the enemies all get arcana checks to recognize the spell, then the enemies know that it's an illusion, thus making it pretty close to worthless.

It would be proper to say only those proficient in Knowledge Arcana could make the check. If you personally know the spell, DC 10. If you don't know the spell but could cast it at your level if you did, DC 15. If it's not on your spell list, DC 15 with Disadvantage. If it's a spell one level above you can cast DC 20. If it's a spell 2 or more levels above what you can cast DC 20 with Disadvantage. If it's a Divine spell it's Knowledge Religion, again need to be proficient. If you don't know if the caster is arcane or divine or the caster is multiclass and could cast either, Disadvantage. If you're a wizard and the spell is of your school, Advantage. It's ok that might counter a Disadvantage or give a clue to the player on a failed roll. You are an expert in your school. Even if the spell is too high a level for you to cast you recognize the familiarity of your school. Advantage also applies if the spell is of your Domain, Oath, or Pact.

Obviously I'm just making this up. It would have been better for the designers to have done this for us for Skills in general so we have a definition we can go by, but that's another topic. It's enough to come with something that does not invalidate illusions. It does mean you would be foolish to cast an illusion spell against an enemy wizard, but why would you be casting an intelligence save spell against one anyway despite this.

[JoeJ]

It does mean you would be foolish to cast an illusion spell against an enemy wizard, but why would you be casting an intelligence save spell against one anyway despite this.

Because ordinarily, they wouldn't get a save of any kind unless they spend either interact with the illusion or spend an action to investigate it.

And you don't have to be a wizard to have high intelligence or be proficient in Arcana. If it can be used to identify spells in combat without wasting an action, I could easily see a BBEG training all of their hobgoblin minions in the skill. All of the more intelligent fiends would likely learn it as well, and certainly dragons would.

[LordBlades]

Arcana checks let you know about spells, right? (don't have book access atm).

Enemy casts an illusion, roll an Arcana check, determine that a spell producing that effect doesn't exist(assuming enemies don't limit themselves to illusions of effects of other spells), therefore making it clear it's an illusion, disbelieve.

[Pex]

Because ordinarily, they wouldn't get a save of any kind unless they spend either interact with the illusion or spend an action to investigate it.

And you don't have to be a wizard to have high intelligence or be proficient in Arcana. If it can be used to identify spells in combat without wasting an action, I could easily see a BBEG training all of their hobgoblin minions in the skill. All of the more intelligent fiends would likely learn it as well, and certainly dragons would.

I have no problem with that.

What would be a problem is if every single foe does that, because then that's the DM metagaming to screw over the players because he hates it they know stuff, like what an NPC is casting.

[Mr.Moron]

The RAW doesn't give us anything to go on so it's a per-GM call. As for how I'd play it.

Well what exactly is "Recognizing a spell being cast", exactly? You're using observation of some combination of the following:

The spell's verbal components (If it has them)
The spell's somatic components (If it has them)
The spell's effects (if it's already been cast)
The spell's effect on local state magical energies, "weave" or the settings equivalent (If you can sense it).

to work out what spell is being cast.

If you're trying to do this quickly say in the space of a reaction, or the space of even less than one reaction (so you can then counter the spell before it finishes casting) you're doing it based only only the components and making the call before all of them have completed. It's kind of playing "Name that tune" where you try and guess a song in the first few notes. Familiarity with the song, how similar it is to others and how familiar you are with those false leads are all going to help.

Given this, I'd say:
Identifying a spell is a reaction. You can use an Intellect(Arcana) check if you have the skill. If the spell being cast is one from your class list, you can make an Intellect Check with your proficiency bonus even without the skill. If you don't have the skill and it isn't on your class list, you can't attempt the check.

The DC of the check is equal to the spells DC+2. You learn the school's spell regardless of the results, just like you could tell the broad "style" of the song even if you don't know it (Jazz is Jazz). If you're a wizard specialized in that school you have advantage on the check. On a success you learn what spell is being cast. If you succeed by +4 over the DC, you get your reaction back/it isn't consumed as you were able to get to the answer in fewer "notes" than is normal.

[JoeJ]

I have no problem with that.

What would be a problem is if every single foe does that, because then that's the DM metagaming to screw over the players because he hates it they know stuff, like what an NPC is casting.

To me, having it at all would feel like the DM is planning to screw over anyone who dares to play an illusionist.

[Mr.Moron]

To me, having it at all would feel like the DM is planning to screw over anyone who dares to play an illusionist.

"Allows for conditions where some abilities are sub-optimal or non-applicable" =/= "Planning to screw someone over".

Jeez louise. You might as well say introducing flying enemies is "Planning to screw over anyone who dares play a guy with swing a greatsword around".

[JoeJ]

"Allows for conditions where some abilities are sub-optimal or non-applicable" =/= "Planning to screw someone over".

Jeez louise. You might as well say introducing flying enemies is "Planning to screw over anyone who dares play a guy with swing a greatsword around".

Introducing flying enemies, no. But if they create a new game mechanic that allows monsters to add 5 to their AC against weapons with the heavy quality, yeah I probably would think that.

[Sredni Vashtar]

Frankly, the idea that someone would cast an illusion spell in combat (or in front of someone meant to believe it for that matter) never occurred to me.

[Mr.Moron]

Frankly, the idea that someone would cast an illusion spell in combat (or in front of someone meant to believe it for that matter) never occurred to me.

Well when I've been playing a wizard I've called out that I'm going to summon some terrible fiend-beast and then use a low level illusion spell to bring up an image of some huge demon thing. It's worked to scare off some duller/more ignorant enemies. Though I'd hardly call foul if the GM declared "Yeah. That dude knows magic and he's knows you're obviously a casting an minor illusion and not really summoning a 20ft tall demon from the depths of hell".

[Tanarii]

Though I'd hardly call foul if the GM declared "Yeah. That dude knows magic and he's knows you're obviously a casting an minor illusion and not really summoning a 20ft tall demon from the depths of hell".especially since Minor Illusion can't be creatures, or bigger than 5ft square. The statue of a 5ft tall fiend you illusion up might not be that terrifying. ;)

[Mr.Moron]

especially since Minor Illusion can't be creatures, or bigger than 5ft square. The statue of a 5ft tall fiend you illusion up might not be that terrifying. ;)

Well not literally the spell "Minor Illusion". "Minor" was meant to be "Low Level" and illusion was a general term. The specific spell I was using was Silent Image. Which is a minor illusion spell, even if it isn't Minor Illusion the spell.

[JoeJ]

especially since Minor Illusion can't be creatures, or bigger than 5ft square. The statue of a 5ft tall fiend you illusion up might not be that terrifying. ;)

Minor Illusion can also create a sound, such as the voice of the BBEG ordering her troops to return immediately, or one of the goblins making insulting remarks about another goblin. Improved Minor Illusion lets you combine sight and sound. A glowing holy symbol hovering in midair, accompanied by the voice of the deity, comes to mind as one possibility. Or a portal to some hellish alternate dimension. And Malleable Illusions lets you change the illusion after you create it, for even more fun.

Looking beyond mere cantrips, Major Image, Phantasmal Force, Programmed Illusion, or Silent Image are all quite powerful and effective spells if used creatively. Mislead can be very handy if you're playing an espionage or heavy political game. Even Disguise Self can be used to help convince somebody that you're powerful enough to cast Polymorph, and therefore much more powerful than you actually are.

All of this fun becomes substantially less so if NPCs can identify which spell you're casting just by watching you.

[Mr.Moron]

Minor Illusion can also create a sound, such as the voice of the BBEG ordering her troops to return immediately, or one of the goblins making insulting remarks about another goblin. Improved Minor Illusion lets you combine sight and sound. A glowing holy symbol hovering in midair, accompanied by the voice of the deity, comes to mind as one possibility. Or a portal to some hellish alternate dimension. And Malleable Illusions lets you change the illusion after you create it, for even more fun.

Looking beyond mere cantrips, Major Image, Phantasmal Force, Programmed Illusion, or Silent Image are all quite powerful and effective spells if used creatively. Mislead can be very handy if you're playing an espionage or heavy political game. Even Disguise Self can be used to help convince somebody that you're powerful enough to cast Polymorph, and therefore much more powerful than you actually are.

All of this fun becomes substantially less so if NPCs can identify which spell you're casting just by watching you.

NPCs that are watching you, have an understanding of magic and pick up on the deception. That's a fair number of cavaets and is at any rate a more interesting game state than "Works perfectly, every time until somebody decides they want to poke the illusion they have no reason to poke", given just how limited and narrow getting saves on these type effects are.

It's not like anything prevents an illusion-focused caster from having to have other effects fall back on. That some educated NPCs in the world might know about such methodology existing and have some chance of recognizing it when used in front of their faces is not some bizarre crusade to neuter all illusionists forever. It's just sensible consequence of the fact that hey, maybe PCs aren't literally the first people in existence to cast an Illusion spell.

[Tanarii]

Well not literally the spell "Minor Illusion". "Minor" was meant to be "Low Level" and illusion was a general term. The specific spell I was using was Silent Image. Which is a minor illusion spell, even if it isn't Minor Illusion the spell.Gotcha. Sorry, I just jumped on it because people gets posting things outside the RAW for Minor Illusion in another thread.

Carry on.

[JoeJ]

NPCs that are watching you, have an understanding of magic and pick up on the deception. That's a fair number of cavaets and is at any rate a more interesting game state than "Works perfectly, every time until somebody decides they want to poke the illusion they have no reason to poke", given just how limited and narrow getting saves on these type effects are.

It's not like anything prevents an illusion-focused caster from having to have other effects fall back on. That some educated NPCs in the world might know about such methodology existing and have some chance of recognizing it when used in front of their faces is not some bizarre crusade to neuter all illusionists forever. It's just sensible consequence of the fact that hey, maybe PCs aren't literally the first people in existence to cast an Illusion spell.

It's bad enough that if a DM implemented that change I'd choose to play something else. Why is it only fun to shut down illusions, even if it's only some of the time? Should NPCs that are watching get a no-action skill roll to negate a Wall of Force? Of knock a druid out of Wild Shape? Or prevent a fighter from using Action Surge? How about allowing a Constitution save to resist a Divine Smite? Wouldn't any of those changes also make the game state more interesting?

Giving characters the ability to identify spells doesn't add anything fun to the game IMO. All it does is needlessly nerf illusionists, and any other spellcasters who rely more on trickery than on raw force.

[Mr.Moron]

It's bad enough that if a DM implemented that change I'd choose to play something else. Why is it only fun to shut down illusions, even if it's only some of the time? Should NPCs that are watching get a no-action skill roll to negate a Wall of Force? Of knock a druid out of Wild Shape? Or prevent a fighter from using Action Surge? How about allowing a Constitution save to resist a Divine Smite? Wouldn't any of those changes also make the game state more interesting?

Giving characters the ability to identify spells doesn't add anything fun to the game IMO. All it does is needlessly nerf illusionists, and any other spellcasters who rely more on trickery than on raw force.

The are absolutely in comparable examples. The gulf between "Is capable of comprehend the difference between an illusion being cast and some other class of spell" and "Can know away tangible objects, or parts of someone else's anatomy" is huge. The first a sensible construction of the game world. Magic is something you can study and magical effects are something produced by an observable means one can have experience with. The second are all tangible things, knowing about them might make it easier to approach the problems they present but can't be sensibly constructed to... destroy them. This line of reasoning is so pants-on-head silly .

[Pex]

Frankly, the idea that someone would cast an illusion spell in combat (or in front of someone meant to believe it for that matter) never occurred to me.

In 3E/Pathfinder I have been known to cast Silent Image for a stone wall even at 1st level. The bad guys don't know I'm not high enough level to cast Wall of Stone. That would be metagame. At worst it gave a one round delay of bad guy actions as they interacted with the wall. Many times the bad guys just accepted the wall's existence and acted accordingly, making the combat easier for the party or allowed us to move from the area as they walked away. I also once cast it to pretend I'm polymorphing into a demon. It partially worked scaring off a few orcs.

[JoeJ]

The are absolutely in comparable examples. The gulf between "Is capable of comprehend the difference between an illusion being cast and some other class of spell" and "Can know away tangible objects, or parts of someone else's anatomy" is huge. The first a sensible construction of the game world. Magic is something you can study and magical effects are something produced by an observable means one can have experience with. The second are all tangible things, knowing about them might make it easier to approach the problems they present but can't be sensibly constructed to... destroy them. This line of reasoning is so pants-on-head silly .

In terms of game mechanics, they're the same. It's not "knowing" something away, it's using any skill to negate a class ability.

So no, they're not incomparably different. If I can make an Intelligence roll to negate an illusion, why can't I make a Charisma roll to negate a Wall of Force at the moment it's cast? Or even a Wall of Stone? It's not natural stone after all, it's a spell. I could destroy it with Dispel Magic, or by causing the wizard who cast it to lose concentration. And Charisma is the ability that several classes use to impose their will on magic. So why can't I use my Charisma to impose my will on that spell without needing to take an action?

The same could be asked of Wild Shape. Why can't I make a Charisma check to prevent a druid from going into Wild Shape in my presence? And why can't I make a Dexterity check to negate a fighter's Action Surge, or at least prevent them from using it to attack me? Maybe my reflexes are just that damn quick.

But the real question is, how does allowing characters and monsters to identify spells make the game better? It adds complication and nerfs certain character concepts, in return for what benefit?

[Temperjoke]

Well, it was mentioned before that if identifying the spell were a danger, then everyone would be trained to find ways to mask the spell they're casting. Of course, if someone was sloppy enough to cast an illusion while one of the intended targets was directly watching, you'd think there'd be consequences.

[Pex]

But the real question is, how does allowing characters and monsters to identify spells make the game better? It adds complication and nerfs certain character concepts, in return for what benefit?

It allows for tactical responses from players of game resources. The wizard can decide if he wants to Counterspell or not. The cleric can decide to cast a remove affliction spell or not. A player can decide if he wants use his Bardic Inspiration buff or Lucky feat use or not. Even if a player can't do anything about whatever spell was cast, just knowing what it was allows them an informed decision of what to do next if it would make a difference. Complexity is not inherently a bad thing. A game is a series of interesting decisions. Knowing information helps players make those decisions. Character concepts aren't nerfed. Players learn to be tactful. They learn it's unwise to cast Phantasmal Force against the enemy wizard but a good idea to cast it against his fighter ally. It doesn't matter the wizard knows what spell was cast. The fighter doesn't. That particular fighter could know. He could be an Eldritch Knight. He could be a Champion but be proficient in Knowledge Arcana anyway. Oh darn. It's a challenge. That does not mean the next fighter the player meets will also have Knowledge Arcana. If every fighter/foe in the world is proficient in Knowledge Arcana, the DM is a donkey cavity.

[Demonic Spoon]

It allows for tactical responses from players of game resources. The wizard can decide if he wants to Counterspell or not. The cleric can decide to cast a remove affliction spell or not. A player can decide if he wants use his Bardic Inspiration buff or Lucky feat use or not. Even if a player can't do anything about whatever spell was cast, just knowing what it was allows them an informed decision of what to do next if it would make a difference

I don't think every decision needs to be made with perfect knowledge for it to be an interesting choice. On the contrary, I would argue that in many cases, the choice becomes far less interesting when the player has perfec tknowledge

Scenario: A level 5 party engages a group of soldiers containing a mage in the back. The party's wizard has counterspell prepared. The enemy mage casts a spell.

If we don't let the players know, then the wizard needs to try to estimate how powerful that spell is likely to be. Is he going to cast Fireball? Or magic missile? If it's fireball, then it's worth it; if it's magic missile, it is not worth it. The difficulty comes in estimating which one. Maybe the DM allows an insight check to figure out if this is some apprentice who just learned magic missile or a seriously seasoned mage to help further inform this decision. However, the decision over whether or not to counterspell is ultimately not clear cut and so the player has to make a hard choice.

Now, let's say the mage gets an Arcana check to identify the spell and passes it. He now knows that the enemy mage is going to cast Fireball. There is now no interesting choice to make. It is unquestionably worthwhile to blow a counterspell to stop a level 5 party from losing most of its hitpoints. It becomes a very straightforward cost/benefit question that is usually quite easy to answer.

[LordBlades]

Minor Illusion can also create a sound, such as the voice of the BBEG ordering her troops to return immediately, or one of the goblins making insulting remarks about another goblin. Improved Minor Illusion lets you combine sight and sound. A glowing holy symbol hovering in midair, accompanied by the voice of the deity, comes to mind as one possibility. Or a portal to some hellish alternate dimension. And Malleable Illusions lets you change the illusion after you create it, for even more fun.


So you cast something (anyone observing you can see that) and then something out of the ordinary happens and you DON'T expect denizens of a magical world with a modicum of intellect to immediately assume it's a result of you casting something?

If an intelligent enemy sees you do some magic, and then a portal to the Nine Hells appears, there are only 2 possibilities :

- you have opened a portal to the Nine Hells
- you have conjured an illusion

One Arcana check later the enemy knows the only way to do the former is by casting a 9th level spell and consuming a rather large diamond (which he presumably he didn't see in your hand), so it's only logical for him to assume you have done the latter.


I don't think every decision needs to be made with perfect knowledge for it to be an interesting choice. On the contrary, I would argue that in many cases, the choice becomes far less interesting when the player has perfec tknowledge

Scenario: A level 5 party engages a group of soldiers containing a mage in the back. The party's wizard has counterspell prepared. The enemy mage casts a spell.

If we don't let the players know, then the wizard needs to try to estimate how powerful that spell is likely to be. Is he going to cast Fireball? Or magic missile? If it's fireball, then it's worth it; if it's magic missile, it is not worth it. The difficulty comes in estimating which one. Maybe the DM allows an insight check to figure out if this is some apprentice who just learned magic missile or a seriously seasoned mage to help further inform this decision. However, the decision over whether or not to counterspell is ultimately not clear cut and so the player has to make a hard choice.

Now, let's say the mage gets an Arcana check to identify the spell and passes it. He now knows that the enemy mage is going to cast Fireball. There is now no interesting choice to make. It is unquestionably worthwhile to blow a counterspell to stop a level 5 party from losing most of its hitpoints. It becomes a very straightforward cost/benefit question that is usually quite easy to answer.

On the other hand, if you counterspell, you will never know if you stopped fireball or magic missile because the spell simply fails. Where's the fun in doing an action but never being able to appreciate the result of said action?

[Demonic Spoon]

So you cast something (anyone observing you can see that) and then something out of the ordinary happens and you DON'T expect denizens of a magical world with a modicum of intellect to immediately assume it's a result of you casting something?

If an intelligent enemy sees you do some magic, and then a portal to the Nine Hells appears, there are only 2 possibilities :

- you have opened a portal to the Nine Hells
- you have conjured an illusion

One Arcana check later the enemy knows the only way to do the former is by casting a 9th level spell and consuming a rather large diamond (which he presumably he didn't see in your hand), so it's only logical for him to assume you have done the latter.

He isn't actually disagreeing with you - he was providing examples where illusions could be used in combat, a use case which the proposed houserule nerfs for the reasons you stated.

[LordBlades]

He isn't actually disagreeing with you - he was providing examples where illusions could be used in combat, a use case which the proposed houserule nerfs for the reasons you stated.

Arcana already allows you to make a skill check to recall lore about spells, presumably also including whether a certain effect was possible to achieve using a spell, and if so which spell.
So no houserules are needed to make casting illusions in combat a bad idea.

[JoeJ]

So you cast something (anyone observing you can see that) and then something out of the ordinary happens and you DON'T expect denizens of a magical world with a modicum of intellect to immediately assume it's a result of you casting something?

Yes, but what did I cast? There are a lot of things happening at once, which one am I responsible for? I might have been casting almost anything that doesn't have an immediate visible effect. Maybe some of the goblins will ignore the voice of the BBEG on the grounds that it might be an illusion. But maybe not all of them will; the consequences of guessing wrong may be quite severe.


If an intelligent enemy sees you do some magic, and then a portal to the Nine Hells appears, there are only 2 possibilities :

- you have opened a portal to the Nine Hells
- you have conjured an illusion

One Arcana check later the enemy knows the only way to do the former is by casting a 9th level spell and consuming a rather large diamond (which he presumably he didn't see in your hand), so it's only logical for him to assume you have done the latter.

If they have to take an action to make the check, then I've cost them an action. And what's the DC on the Wisdom (Perception) check to notice whether or not I have a diamond? In the middle of a very chaotic situation, how certain are they that I didn't have one? And you're forgetting a third possibility: that I've invented a new spell (there are rules for that in the DMG, after all).

More importantly, however, a world in which instant identification of spells is possible is almost certainly a world in which a lot more people are proficient in Arcana. If it's just the BBEG's chief wizard telling the troops to walk through the "harmless illusion" while he remains safely in back, that's a very difference scenario from their own sergeants telling them that before personally leading them through.

[JoeJ]

If every fighter/foe in the world is proficient in Knowledge Arcana, the DM is a donkey cavity.

But if the PCs use it against every spell cast by every enemy in every fight, that's okay, right? The fog of war should only ever work in one direction?

[LordBlades]

Yes, but what did I cast? There are a lot of things happening at once, which one am I responsible for? I might have been casting almost anything that doesn't have an immediate visible effect. Maybe some of the goblins will ignore the voice of the BBEG on the grounds that it might be an illusion. But maybe not all of them will; the consequences of guessing wrong may be quite severe.

Because it just happened that on your round, just after you cast something with no obvious effect the BBEG called them back, right? Goblins might be fooled by that, but not anyone with 2 brain cells to rub together (especially if the order to fall back doesn't make much sense to begin with).




If they have to take an action to make the check, then I've cost them an action. And what's the DC on the Wisdom (Perception) check to notice whether or not I have a diamond? In the middle of a very chaotic situation, how certain are they that I didn't have one? And you're forgetting a third possibility: that I've invented a new spell (there are rules for that in the DMG, after all).

Fair point about the action, but I'd imagine a 5000 GP diamond would be quite big. Using RL conversion of Gold (1 oz of gold is about 100$, 1 gp=1/3 oz.) to $, a 5000 GP diamond would be worth 1.75 mil $. I don't expect you'd miss somebody taking that out of their pocket in the middle of the combat.

[Fwiffo86]

Because it just happened that on your round, just after you cast something with no obvious effect the BBEG called them back, right? Goblins might be fooled by that, but not anyone with 2 brain cells to rub together (especially if the order to fall back doesn't make much sense to begin with).





Fair point about the action, but I'd imagine a 5000 GP diamond would be quite big. Using RL conversion of Gold (1 oz of gold is about 100$, 1 gp=1/3 oz.) to $, a 5000 GP diamond would be worth 1.75 mil $. I don't expect you'd miss somebody taking that out of their pocket in the middle of the combat.

1 gram of diamond cut reasonably well sells in the area of $80,000.00. Using your estimated value, that would be almost a 22 gram diamond. 1 pound equals 453.592 grams. So I would say that a 5000 gp diamond at best, is no bigger than a fingernail. Easily palmable, and very easy to keep out of direct line of sight.

[Pex]

I don't think every decision needs to be made with perfect knowledge for it to be an interesting choice. On the contrary, I would argue that in many cases, the choice becomes far less interesting when the player has perfec tknowledge

Scenario: A level 5 party engages a group of soldiers containing a mage in the back. The party's wizard has counterspell prepared. The enemy mage casts a spell.

If we don't let the players know, then the wizard needs to try to estimate how powerful that spell is likely to be. Is he going to cast Fireball? Or magic missile? If it's fireball, then it's worth it; if it's magic missile, it is not worth it. The difficulty comes in estimating which one. Maybe the DM allows an insight check to figure out if this is some apprentice who just learned magic missile or a seriously seasoned mage to help further inform this decision. However, the decision over whether or not to counterspell is ultimately not clear cut and so the player has to make a hard choice.

Now, let's say the mage gets an Arcana check to identify the spell and passes it. He now knows that the enemy mage is going to cast Fireball. There is now no interesting choice to make. It is unquestionably worthwhile to blow a counterspell to stop a level 5 party from losing most of its hitpoints. It becomes a very straightforward cost/benefit question that is usually quite easy to answer.

That's why it's a skill check and not automatically known. Not having perfect knowledge of everything does not mean never, ever having perfect knowledge of something. It's not verboten for PCs to know stuff.


But if the PCs use it against every spell cast by every enemy in every fight, that's okay, right? The fog of war should only ever work in one direction?

It would only be the PCs proficient in Knowledge Arcana. Not every PC would be such. It's still a roll. So to answer your question, yes, because going with the wizard stereotype such a character should be quite familiar with spellcasting and its intricacies.

It's also ok for some bad guys to be proficient in Knowledge Arcana and use that knowledge against PC spellcasters as applicable. Not wanting every foe to be proficient is not the same thing as preferring no one ever is except the PCs. It's not so extreme.

[Demonic Spoon]

That's why it's a skill check and not automatically known. Not having perfect knowledge of everything does not mean never, ever having perfect knowledge of something. It's not verboten for PCs to know stuff.

It's also not required that they be able to know things about a particular topic. The question is whether or not it is good for the game that PCs be able to do this. "It results in more interesting decisions" is the only positive argument being made in favor of allowing this (as opposed to just arguing against benefits of restricting it).

[JoeJ]

It would only be the PCs proficient in Knowledge Arcana. Not every PC would be such. It's still a roll. So to answer your question, yes, because going with the wizard stereotype such a character should be quite familiar with spellcasting and its intricacies.

If the PC with that proficiency is a member of the party then it's a difference without meaning. The PCs get to roll for every spell cast by every enemy in every fight.


It's also ok for some bad guys to be proficient in Knowledge Arcana and use that knowledge against PC spellcasters as applicable. Not wanting every foe to be proficient is not the same thing as preferring no one ever is except the PCs. It's not so extreme.

So you want the PCs to always have a significant advantage, but the bad guys only get to have it some of the time or you'll accuse the DM of being a jerk.

But Arcana is a skill, not a tool, so lack of proficiency doesn't stop anybody from attempting it; they just don't get to add their proficiency bonus. Any creature with an Intelligence score can try, and if there's no cost, then every creature with a score high enough to have any chance whatsoever of succeeding should try. For every spell cast. Even if they can only succeed on a 20, it's still worth doing.

That might be great for an abjurer, and not matter hugely to an evoker. But it makes being an illusionist a lot riskier. To me, that makes the game less fun. I wouldn't quit just because the DM instituted this rule, but it would definitely affect what kind of character I'd play.

[DivisibleByZero]

Yes, there was a Spellcraft check in 3.X. No, there isn't a Spellcraft check in 5th. This is deliberate.

No, there's no RAW way to know what spell is being cast. This is deliberate.

Yes, that means if an enemy is casting as spell, you have to decide whether you think it's worth blowing a 3rd level (or higher) slot on countering it. Given that's its an enemy casting the spell, in combat, you've a pretty good chance of it not being harmless (either it will be detrimental to you, or beneficial to them). This is deliberate.

^ this ^

And since no one has addressed this yet:


However, skills are actions when used in combat.I am virtually certain this is incorrect unless you can cite a general rule somewhere?

There is nothing in the PHB that makes this a general rule.

Actually, there is.

PHB, page 192, Actions in Combat
When you take your action on your turn, you can take one of the actions presented here, an action you gained from your class or a special feature, or an action that you improvise. Many monsters have action options of their own in their stat blocks.
When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

Doing something that requires an Ability Check falls under the purview of the portion that I emboldened, which leads us to:

PHB, sidebar, page 193, Improvising an Action
Your character can do things not covered by the actions in this chapter, such as breaking down doors, intimidating enemies, sensing weaknesses in magical defenses, or calling for a parley with a foe. The only limits to the actions you can attempt are your imagination and your character’s ability scores. See the descriptions of the ability scores in chapter 7 for inspiration as you improvise.
When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

Breaking down doors, Str check.
Intimidating enemies, Cha (intim) check.
etc etc etc, and these things require your Action.
So, in short, yes, using a skill in combat would be an improvised action, which uses your Action.

[Demonic Spoon]

The fact that the DM is allowed to offer additional options for actions does not imply that any kind of d20 roll the DM might have you perform necessarily costs an action. That section just says, in the section which contains a list of all of the actions you might take in the most structured part of the game (combat), that actions not covered by that section still exist and the DM will tell you how they work. It's to give the DM the power to improvise, not to take away other powers the DM already has.

[DivisibleByZero]

The fact that the DM is allowed to offer additional options for actions does not imply that any kind of d20 roll the DM might have you perform necessarily costs an action. That section just says, in the section which contains a list of all of the actions you might take in the most structured part of the game (combat), that actions not covered by that section still exist and the DM will tell you how they work. It's to give the DM the power to improvise, not to take away other powers the DM already has.

I'll repeat myself, and embolden the important parts.

PHB, sidebar, page 193, Improvising an Action
Your character can do things not covered by the actions in this chapter, such as breaking down doors, intimidating enemies, sensing weaknesses in magical defenses, or calling for a parley with a foe. The only limits to the actions you can attempt are your imagination and your character’s ability scores. See the descriptions of the ability scores in chapter 7 for inspiration as you improvise.
When you describe an action not detailed elsewhere in the rules, the DM tells you whether that action is possible and what kind of roll you need to make, if any, to determine success or failure.

See the descriptions of the ability scores in chapter 7 for inspiration as you improvise.
You know, the exact place where the Ability Checks (also known as skills) are described.
To paraphrase:
Your character can take a bunch of other Actions not listed in this chapter, such as <ability check>, or <ability check> or, <ability check>, or <ability check>. See the descriptions for the different ability checks for inspiration.

Nope. It doesn't say anything at all like I just described....

[Pex]

If the PC with that proficiency is a member of the party then it's a difference without meaning. The PCs get to roll for every spell cast by every enemy in every fight.



So you want the PCs to always have a significant advantage, but the bad guys only get to have it some of the time or you'll accuse the DM of being a jerk.

But Arcana is a skill, not a tool, so lack of proficiency doesn't stop anybody from attempting it; they just don't get to add their proficiency bonus. Any creature with an Intelligence score can try, and if there's no cost, then every creature with a score high enough to have any chance whatsoever of succeeding should try. For every spell cast. Even if they can only succeed on a 20, it's still worth doing.

That might be great for an abjurer, and not matter hugely to an evoker. But it makes being an illusionist a lot riskier. To me, that makes the game less fun. I wouldn't quit just because the DM instituted this rule, but it would definitely affect what kind of character I'd play.

Since the ability is not specifically in the rules, and it's already admitted something the DM needs to house rule, I gave my spur at the moment time of writing way of doing it up thread and said only those proficient in the skill would be allowed to roll and that's what I've been using as reference, so no, not every creature with an Intelligence score gets to do it. I might have to concede all bards can due to Jack of All Trades, once they get the ability, but they still follow the DCs of not being on their spell list and being of higher level than they can cast. This would also be true of all opposing NPC bards.

I also have absolutely no problem with a PC being able to do something that not every NPC or monster gets to do. I've been playing with this knowledge ability since 2E and Spellcraft without any issues. It's not suddenly a game breaker just because it's 5E.

[JoeJ]

Since the ability is not specifically in the rules, and it's already admitted something the DM needs to house rule, I gave my spur at the moment time of writing way of doing it up thread and said only those proficient in the skill would be allowed to roll and that's what I've been using as reference, so no, not every creature with an Intelligence score gets to do it. I might have to concede all bards can due to Jack of All Trades, once they get the ability, but they still follow the DCs of not being on their spell list and being of higher level than they can cast. This would also be true of all opposing NPC bards.

Yes, you did state that. That is not the way skills generally work in 5e, however, so a DM who does it a little differently and rules that any creature can make an Intelligence check to identify a spell being cast is not being a jerk, they're just being consistent.


I also have absolutely no problem with a PC being able to do something that not every NPC or monster gets to do. I've been playing with this knowledge ability since 2E and Spellcraft without any issues. It's not suddenly a game breaker just because it's 5E.

Not a game breaker =/= good reason to add a new rule. Particularly one that both privileges some characters over others, and makes player choices less meaningful.

[Demonic Spoon]

Nope. It doesn't say anything at all like I just described....

It does not, no. It does not say that every ability check you might make is an action. You are reading from the Actions in Combat section, which starts off with: When you take your action on your turn, you can...

The section exists to answer the question "What can I do with my action". There are many things that you can do in combat that are not described in this section - bonus actions, reactions, moving up to your speed, and item interactions. None of those things are covered in the actions in combat section, and yet they obviously are things you can do (and also things that may require ability checks).

Per "other activity on your turn": You can communicate however you are able, through brief utterances and gestures, as you take your turn. Are you suggesting that nothing that you could do via this communication could ever require a Persuasion or a Deception check?

in the "Movement and position" section, you are referred to Chapter 8 for special kinds of moving such as climbing and jumping. These kinds of movements involve ability checks (usually Athletics) and those clearly do not require actions.

[Fwiffo86]

in the "Movement and position" section, you are referred to Chapter 8 for special kinds of moving such as climbing and jumping. These kinds of movements involve ability checks (usually Athletics) and those clearly do not require actions.

Movement has its own rules and guidelines. Any activity that stems from movement is governed by a different paradigm and is not applicable to spending an action to make a proficiency check debates.

[Pex]

Yes, you did state that. That is not the way skills generally work in 5e, however, so a DM who does it a little differently and rules that any creature can make an Intelligence check to identify a spell being cast is not being a jerk, they're just being consistent.



Not a game breaker =/= good reason to add a new rule. Particularly one that both privileges some characters over others, and makes player choices less meaningful.

It's still an inherent house rule. That's why for those DMs who would implement it it's suggested only let those proficient in Knowledge Arcana/Religion make skill checks to identify spells being cast so that not everyone gets to identify PC casting spells and Illusionists get to do their thing. It's not an unreasonable house rule in general that for any skill only those proficient in it get to attempt certain things related to that skill. It's a way to have a difference between proficiency and not proficient more than just a +#, but that's an issue that's been discussed in length before about 5E Skill use in general in other threads.