In order to Identify a spell being cast (XGtE p85)

a character can use their reaction to identify a spell as it's being cast,

This is a problem because Counterspell (PH p228) also requires a reaction.

So if my intent is to identify the spell being cast and then counter it, I am unable to do both at the same time.

The only work around I have thought about is having a familiar attempt to identify the spell for me, and then telepathically relay the information so I can then counter it... But he's not terribly smart..

Any other options or solutions?


2 Answers 2


Xanathar's text is just a ruling guideline, not a core rule

So, the work around is just house-rule different than the optional rule provided in XGtE.

Let us make this clear:

Nothing herein is required for a D&D campaign-this is not a fourth core rulebook- but we hope it will provide you new ways to enjoy the game.

Check this Q&A to understand what in XGtE are actual rules and what are just ruling guidelines.

And being honest, I believe this is a bad ruling guideline. Using your entire reaction to simply identify a spell seems... too much. "Oh hey I will use my reaction to see what spell they are casting" - "Oh, a Fireball". Fire explodes. Yeah, that was obvious...

Except for identifying long-lasting effects, that's pretty much useless.

Crawford, the lead developer for 5e, has made a tweet stating his own ruling here1:

As DM, I let you ID a spell if you know it (or it's on your class's spell list) and if you perceive V, S, or M. #DnD

I use this along the Arcana check described in XGtE.

the character can make an Intelligence (Arcana) check with the reaction or action. The DC equals 15 + the spell's level.

The ruling is basically: if you know the spell or have it prepared, you automatically succeed on knowing that the spell is being cast (although note: you don't know what level the spell is being cast as, so that may still trick your counter spell). If you can learn or prepare that spell (i.e., it is in your class list), you can try the check (without spending a reaction). If it's on your class list, but you can not learn it (i.e., it's a higher level than you have spell slots for), I simply tell them the spell is too advanced for them to understand (so at least they know the spell is going to hit hard haha).

A few reasons I do it:

  • It's frustrating for the players to use counterspell on Create Water1 or another "whatever" spell.
  • I feel like Spellcasters should be able to recognize a spell an enemy is casting, especially if it's a spell they themselves know and use frequently. This is based on the assumption that the verbal and somatic components are somewhat universal (unlike, for example, the way a Wizard writes the spell in the spellbook, which is unique to the Wizard). I'm not sure this is explicitly stated anywhere in the core books, but that's how I interpret it, and many spells actually described what are their components, so it's fair to assume they are standard.
  • Spellcasting NPCs are not exactly the most common enemies the parties will face in my campaigns anyway.
  • I find that it is hard, for me, as the DM, to be fair about "ah but the NPC doesn't know the spell the PC is casting either". The player literally just screamed the name of the spell and its description in my face, it's hard to simply ignore that knowledge when making the decision "should the NPC counterspell or not?" - so simply allowing them to know makes my life way easier and the game more fair. You (as a DM) or your DM may not have this problem - I do.

Honestly, I have even simply stated - sometimes unintentionally - "The Night Hag is casting Lightning Bolt", i.e., spelling out what is the spell to the players. So far, I didn't really have a problem with this ruling.

If you are not the DM, ask the DM to allow you to do that.

1 This tweet was pre-XGtE, but the point is that there are other ways to rule how identifying a spell works other than the one that was ultimately published as optional rule.

2 The example is obviously a joke, before anyone tells me "why is the NPC casting create water mid-combat?" or anything like that.

  • \$\begingroup\$ They're casting create water mid combat to get the PC with the ability to counterspell to waste their reaction before their ally casts the important spell. \$\endgroup\$ Commented Jul 20, 2020 at 1:59

So if my intent is to identify the spell being cast and then counter it, I am unable to do both at the same time.

Correct - this is intentional.

If you choose to use Counterspell, you use it without knowing what you are (attempting to) counter. In fact, only if you fail will you know what the spell is because it will be cast.

Look, if you are thinking of using Counterspell then you probably think that letting the target cast the spell is going to be bad, so [shrug]. You don’t know if you are countering a 9th level or a cantrips so you pays your money and you takes your chances.

This works both ways of course, hostile spellcasters don’t know what spell you are casting either.

Your familiar idea, while good, doesn’t work and not just because your familiar has a negative Arcana bonus. Your and your familiar’s reactions fire off the same trigger, someone casting a spell, which means they happen simultaneously. If you use the XGtE optional tie breaking rule to allow your familiar to go first, even if they succeed, they can’t communicate to you because it’s not their turn:

You can communicate however you are able, through brief utterances and gestures, as you take your turn.

  • 1
    \$\begingroup\$ Yeah that doesn't work for me. Other versions of D&D let you identify the spell as a free action, or as part of the counter. The random element might make sense for a sorcerer or a warlock.. but a Wizard went to school and studied this stuff. That knowledge should be readily available. \$\endgroup\$ Commented Jul 18, 2020 at 3:27
  • 7
    \$\begingroup\$ @SamLacrumb Then, I guess, play those other versions or make a house rule. \$\endgroup\$
    – Dale M
    Commented Jul 18, 2020 at 3:35
  • 6
    \$\begingroup\$ Technically, it's not even a "house-rule" to have identifying a spell not require a reaction, because it's an optional rule in the first place (by virtue of appearing in Xanathar's and not being stated anywhere else). There's no rule on the subject either way in the core books; the PHB doesn't say one way or the other whether you know what spell someone's casting (whether or not you're counterspelling it). \$\endgroup\$
    – V2Blast
    Commented Jul 18, 2020 at 5:51
  • 3
    \$\begingroup\$ @Pleasestopbeingevil: Ah. I'd disagree that the default is "you can identify the spell for free". The default is "there's no rule on this, so it's up to the DM to make a ruling". \$\endgroup\$
    – V2Blast
    Commented Jul 18, 2020 at 6:39
  • 1
    \$\begingroup\$ I think you are reading too much into "as you take your turn". That section is on your turn and not on communication, so it is unlikely that was intended as a restriction. Such rules are usually explicitly stated, rather than left to the reader to infer from random sentences. \$\endgroup\$
    – Szega
    Commented Jul 18, 2020 at 7:28

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