D&D 5E Xanathar's Guide: How does identifying a spell + Counterspell work?

[mikebr99]

At my table... I'm championing...

"Sometimes a character wants to identify a spell that someone else is casting or that was already cast. To do so, a character can use their reaction (or combined with Counterspell reaction) to identify a spell as it’s being cast (and counter if able)..."


So it's either a reaction or combined with the Counterspell reaction... if you can make the arcana check (DC equals 15 + the spell’s level) then you can counter however you like... if you fail the arcana check then you have to guess which spell slot to use.

I'm an 11th level abjurer at the moment... so I don't really need to find out what I need to counter before I cast counterspell anyway.

Mike

 

[Dausuul]

Well, as I stated previously, the Xanathar rule is dumb and shouldn't be used.

Yeah, we agree on that. We're just debating the precise extent of its dumbness.

But assuming that you are using that optional rule - specific still trumps general. And the shield spell specifically allows itself to be cast in reaction to being targeted by the magic missile spell.

Specific trumps general, but the shield spell does not specify that it gives you any special insight into the spell being cast. It just says that if that spell happens to be magic missile targeting you, you can cast shield in response.

I think by a strict reading of the rules, you would have to declare shield blindly, and then if the spell isn't magic missile, the DM tells you that your attempt to cast shield fails.

 

[Caliban]

Yeah, we agree on that. We're just debating the precise extent of its dumbness.


Specific trumps general, but the shield spell does not specify that it gives you any special insight into the spell being cast. It just says that if that spell happens to be magic missile targeting you, you can cast shield in response.

I think by a strict reading of the rules, you would have to declare shield blindly, and then if the spell isn't magic missile, the DM tells you that your attempt to cast shield fails.

Would you also make them lose the spell slot and their reaction if they are unable to cast Shield?

 

[Dausuul]

Would you also make them lose the spell slot and their reaction if they are unable to cast Shield?

Well, like you, I wouldn't apply this rule in the first place. But if for whatever reason I were determined to run a game strictly by RAW, I would say no: You do not lose your reaction or your spell slot, because you never get the opportunity to cast the spell in the first place.

In effect, you can determine whether or not a spell is magic missile being cast at you by trying to shield against it. But if you don't know shield, or you aren't willing to use it right now, you can't.

 

[Buboz]

You can't.



For most tables, yep. Crawford has said on Twitter that this is how he always thought of counterspell working, but there's a pretty wide range of people I've seen on Twitter, Reddit, and here that didn't play this way at all and don't really like it.

Crawford has also said that he would allow another character to use their reaction to identify the spell and then tell another character who could then counterspell the spell. Why he thinks introducing another person into the mix would take less time I'm not sure, but there you go. It's a mechanics over narrative answer if ever there was one, which is exactly what I expect from Crawford.



I think it's an actively bad rule. Everything about it is fine if spell identification doesn't take a reaction, but the reaction part is actively bad because of how counterspell is written.

The real problem isn't so much that counterspell would be random. Although making it 50% random more often does significantly harm the spell -- keep in mind that the 50% chance isn't why dispel magic was never used to counter spells in previous editions; it's because doing that required a readied action! No, the real problem here is that it provides incentives for the players and DMs to cheat.

Let me explain the problems:

First, play slows down for the DM's turns -- and not just because of the extra die roll although you do need to consider that as well. When using this rule and the DM casts a spell, instead of saying: "The lich casts fireball," she now has to say, "The lich casts a spell. Any reactions?"

However, it goes beyond that. Play slows down for the PC's turns, too. See, any spellcaster in the party is likely to eventually say, "Hey, if the players have to make decisions about their characters' reactions without knowing what the spell is, then the DM should be in the same boat for her NPCs." Now the PCs are going to say, "I cast a spell. Do any NPCs have reactions?" Sure, the DM could rule the PCs must announce the spell, but that's pretty clearly not fair. And, yes, the DM can argue that she's playing every NPC and already has out-of-character knowledge and so will judge fairly, but the PCs can actually argue the same. So now you're back to arguing about why this information is even hidden at all.

Let's say you finally agree that it's most fair for everybody to keep the spell hidden. Well, you've now just secretly encouraged this:

PC: (thinking) I'm going to try casting fireball.
PC: I'm casting a spell. Any reactions?
DM: The lich casts a spell as a reaction. Any reactions?
PCs: No reactions.
DM: The lich casts counterspell level 3.
PC: (lie) You counter a magic missile.

Next turn:

PC: (thinking) I'm going to try casting fireball again.
PC: I'm casting a spell. Any reactions?
DM: No reactions.
PC: I cast fireball.

Yeah. That's some garbage, isn't it? Now, yes, everybody plays with people who are not going to cheat. However, there's a big difference between trusting your group not to cheat, and not adopting rules that allow you to cheat with no real chance of getting caught.

Obviously the DM could similarly lie to the PCs, but, frankly, the above feels even more wrong.

The only fixes I can see are:

1. Make spell identification not require a reaction, but still require that you haven't been prevented from making a reaction (e.g., shocking grasp, etc.). This is similar to how the opportunity attacks on Mark works on DMG p271. If you wanted to keep to the spirit of the optional rule, you could say that you're limited to one spell identified in a round. Alternately, you could rule that spell identification uses the "free" reaction wording like some abilities: "This doesn't expend your reaction, but you must not have spent your reaction to do this." There's a dozen ways to word this to work in slightly different ways. Edit: Keep in mind, the only reason Crawford gave on Twitter for making it take a reaction is because he didn't want to slow down the game for every spell to be identified.

2. Ignore the rule and play how you were. Remember, Xanthar's Guide is full of optional and alternate rules (with the exception of the 10 rules on page 5). They're not necessarily supposed to be expansions on how you should already be playing the game. Never let a book tell you that the way you're playing the game with all parties happy and having fun is wrong and needs to change. Not even the PHB or DMG trump what you want to do at your table.

Honestly, I feel like it wouldn't feel quite so bad if counterspell didn't have the "At higher levels" option. I wish the spell hadn't been given that at all. Still, if you remove that you're still not fixing the above cheating problem. What are you going to do for that? Make the player write down what they cast and reveal it after reactions? I guess that would be a reason to buy those spell cards that have been sold out everywhere for a year.

Thanks for your detailed explaination. I'm just wondering why you need to identify a spell in order to counterspell it.
Counterspell text says: "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."

Here is how I assume to make it works:
When someone (PC or NPC) see casting a spell, there could be as reaction, like counterspell. In this moment only, everybody must knows the casted spell name, and if it is 3rd level or lower, counterspell automatically works, otherwise will be necessary to roll a dice and see if the result is enough to dispel casted spell.
Doing so, you (i.e.) could counterspell a 9th level spell, if your dice is high enough, but you could aslo counterspell a Magic Missile level 1. If then, someone other uses his reaction to identify the spell, then you could choose to use counterspell it or not.

 

[Horwath]

We always used Arcana for free when identifying spells, same as any check to recall knowledge about something.
In that moment you either know it or not.

 

[jayoungr]

Here is how I assume to make it works:
When someone (PC or NPC) see casting a spell, there could be as reaction, like counterspell. In this moment only, everybody must knows the casted spell name, and if it is 3rd level or lower, counterspell automatically works, otherwise will be necessary to roll a dice and see if the result is enough to dispel casted spell.

Actually ... why do you have to know the name of the spell in order to counterspell it? You don't need to know exactly what spell you're dispelling with dispel magic, so why should counterspell be different?

 

[TheSword]

In response to the OP it’s a dumb rule.

Allow a ‘free’ arcana or religion check (Arcane or divine respectively) to identify the spell DC 15+Spell level.

If they use their reaction for it 10+spell level, as they give the casting more attention.

Problem solved.

 

[Li Shenron]

I'm just wondering why you need to identify a spell in order to counterspell it.

Actually ... why do you have to know the name of the spell in order to counterspell it?

You don't need to know the spell to be able to counterspell it.

You want to know the spell to decide if it's worth spending a slot to counterspell it.

 

[Umbran]

You don't need to know the spell to be able to counterspell it.

You want to know the spell to decide if it's worth spending a slot to counterspell it.

This is a three-year-old discussion, for anyone who cares.

That said... in play we honestly haven't seen too much trouble with not knowing for sure. The counterspell comes out with an understanding of the tactical situation at hand. Is the bad guy wasting their action with a piddly spell at this moment, or are they likely breaking out a big gun? That's generally sufficient.