Do monsters with Spellcasting x/day expend their spells when counterspelled?

Question

Counterspell (p. 258, PHB) says:

On a failed save, the spell dissipates with no effect, and the action, Bonus Action, or Reaction used to cast it is wasted. If that spell was cast with a spell slot, the slot isn’t expended.

My question is: how does counterspell interact when you counter an x/day spell provided by the Spellcasting feature in a monster stat block. Does it get back the daily use, or not?

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The lengthy explanation of why I have problems figuring this out follows.

Only some legacy monsters use spellcasting with explicit spell slots currently. For example, the Archmage from the 2014 MM does. P. 9 tells us:

A monster with the Spellcasting class feature has a spellcaster level and spell slots, which it uses to cast its spells of 1st level and higher

and the Archmage's spellcasting entry spell list (p. 342) reads like this:

Cantrips (at will): fire bolt, light, mage hand, prestidigitation, shocking grasp
1st level (3 slots): detect magic, identify, mage armor*, magic missile
2nd level (3 slots): detect thoughts, mirror image, mistry step
[etc]

There has been no version that supercedes this legacy 2014 MM Archmage. So, if you counter his or her spells, they get to keep the slot.

However, for other casters that appear in Mordenkainen Presents: Monsters of the Multiverse, the way their spellcasting looks has been changed, to make it more manageable for the DM. Instead of a list of spells and spell slots, it now looks like this (example from the Conjurer), and we can expect spellcasting monsters in the new 2024 MM to follow this more recent pattern:

At will: dancing lights, mage hand, prestidigitation
2/day each: fireball, mage armor, unseen servant
1/day each: fly, stinking cloud, web

Innate Spellcasting from the 2014 MM (p. 9) that uses the same format says:

Unless noted otherwise, an innate spell of 1st level or higher is always cast at its lowest possible level and can't be cast at a higher level.

and does not say Innate Spellcasting uses slots. However, the feature is not called "Innate Spellcasting", it is still called "Spellcasting", and I was unable to find any header material in the MP:MotM book that says that this is a new version of spellcasting that does not use spell slots.

If you look at the monster stat block, it does not provide spell slots of different levels, and for the 2/day spells fireball is a level 3 spell while mage armor and unseen servant are level 1 spells, for the 1/day spells, fly and stinking cloud are level 3 spells, and web is a level 2 spell. This would imply there is a total of 4 level 1 slots, 1 level 2 slot, and 4 level 3 slots, a slot progression that does not make any sense. Moreover it would be anathema to making work easier for the DM if the idea was that the DM has to figure out the slots by looking up the base spell levels for all the spells. Because of this I think it is probably the idea that these spells are not meant to be cast with spell slots, nevermind what the Spellcasting entry in the 2014 MM tells us, and they just forgot to provide an updated version of the description of the Spellcasting feature.

There also is this snippet from the 2024 PHB, on p. 234 about Casting without Slots:

Special Abilities. Some characters and monsters have special abilities that allow them to cast specific spells without a spell slot. This casting is usually limited in another way, such as being able to cast the spell a limited number of times per day.

But if that is so, then when you Counterspell the spell of a monster using this format, the way Counterspell is written, they do not get back the daily use, as there is no slot, and they get back no slot.

That also would mean that for the time being, PC and leveled NPCs, as well as some NPC spellcasters would have the ability to repeatedly cast their top end spell if you counter it (because they get the slot back) while others NPCs or monsters, using the new format, would not have the ability to repeat their spell, an inconsistency I would find highly dissatisfying (but that may just be the case -- there are lots of rules that are somewhat asymmetric to the benefit of the PCs).

Answer 1

Yes, which is fine

Monster vs Character rules are asymmetrical. This has always been the case. Monsters typically can do many more things than characters, however this particular asymmetry seems to favor characters. A given person’s "dissatisfaction" has no bearing on that.

Most monsters don't have to budget resources because they have short lives. Characters, on the other hand, have to budget through an adventuring day. So, this asymmetry may be appropriate and will almost never matter.

If a GM wants to ensure parity on this niche issue for some reason (e.g. a recurring antagonist), they can create Hostile characters using standard character creation options, whom use spell slots.

Answer 2

RAW is compatible with either using up or not limited casting resources other than slots. (e.g. Innate Spellcasting or charges from an item.)

Unlike 2014 where even the interaction with spell slots wasn't spelled out in the description, 2024 Counterspell is specific about spell slots. But it says nothing about other cases so it's up to us to fill in that blank.

So either:

• It makes narrative sense that CS interacts with other spell-powering resources the same way it does with spell slots, as I argued in the 2014 version of this question (Innate spellcasting x / day: is it x attempts or x successful casts?). 2024 CS does mention spell slots specifically so this isn't the only possible reading.
  But RAW doesn't explicitly say what happens for resources other than spell slots, so that leaves room for the DM to make a ruling that makes sense for the narrative of how magic works in their game world.

• Or you read the 2024 CS's description as a special case for spell slots, and assume the non-mention of any other resources was intentional and significant, implying that they are consumed.

  CS still says "the spell dissipates with no effect" which is pretty similar to the 2014 wording "spell fails and has no effect" which apparently was meant to imply that the resource was consumed, so you could argue that's what happens for cases other than spell slots which are a specific exception to that previous statement.

  It also says "the action, Bonus Action, or Reaction used to cast it is wasted". That sounds to me like it's just talking about action economy during the turn, but for Innate Spellcasting you could also argue that it's also the x/day action that initiated the spellcasting attempt being wasted.

Judging purely on rules wording without considering narrative or what makes sense or what might have been meant or intended but had to be kept short, it's easy to argue for the second reading, that only spell slots are not consumed.

And there are ways to narratively justify it, like that intelligent spellcasters who have to consciously manage their spellcasting energy are more able to avoid expending it than a magic item which has been activated, or a monster who doesn't think about how they're casting a spell, they just do.

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I think it makes more narrative sense for counterspell to treat non-spell-slot resources the same as spell slots, so unless that ends up not being fun at the table, I'd go with it.

The 2024 CS change is a big nerf to what was a very strong spell, e.g. able to use up a 1/x PW: Kill or Meteor Swarm ability. So of course players are going to miss that, and like it when they can still do it vs. innate spellcasters. But unless there's some significant differences between the spells that innate-spellcasting monsters have vs. monsters with the Spellcasting trait, or some other combination of factors, it seems hard to justify CS being a lot stronger vs. innate spellcasters.

Maybe Innate spellcasters typically have higher Con saves than typical NPC spellcasters? The new CS gives the defender a Con save instead of the CSer an ability check. So getting them to fail is rarer, and a reward of using up their ability to try again compensates?

This last section is all just spitballing about which ruling might play better at the table, since I still think both are compatible with RAW.