Crawford's tweet on the subject indicates that it is as simple as the spell being on the caster's class' spell list:
What ultimately makes something a [class] (wiz/sorc/etc) spell? Is having it on your spell list enough, even if you're not high enough to cast/don't know it/don't cast via Spellcasting? I.E., can a level 1 Sorc Wild Magic Surge off of Luck Blade's wish despite not knowing it yet?
@SymphFan, 4:12 PM - 26 Jun 2018
A class's spell list is the list of that class's spells. #DnD
@JeremyECrawford, 5:57 PM - 26 Jun 2018
HoweverTo provide an answer to this, between tweets no longer being official rulings and feeling that there are a few gaps in that simple statement, I think it's worth enumerating the edge caselot of rules need to consider ahead of that bit of advicebe inferred from context, the Sage Advice compendium, and RAI tweets from Crawford.
Here'sMy recommendation would be to go down the following list of "howquestions in order until you get an applicable answer, then stop. I'll do my best to determine ifexplain why under each question, and give a spell is(very much non-exhaustive) example of a particular class'" guidelinescase that I've inferred from other rules and rulingsfits the question.
(Note that I'm attempting to list generalized rules; there may be features/abilities/items/etc. that are explicit, in decreasing priorityblatant exceptions to these.)
1. TheIs the spell is being directly cast from a non-Spellcastingdirectly through one of your class features that is not Spellcasting/Pact Magic class feature.?
This isn't explicitly stated in the books, but I believe this to be true for features like the warlock's Eldritch Invocations that allow casting particular spells that aren't on the warlock list, such as Dreadful Word allowing the casting of *confusion*. *Confusion* isn't explicitly marked as a warlock spell, and it isn't on the warlock spell list, but it seems clearly meant to be considered a warlock spell. RAI agrees, as well:Qualifying/valid example:
- A warlock casts confusion through the "Dreadful Word" Eldritch Invocation.
If yes, the instance being cast in this case is a 'class' spell of the class granting that ability.
Reasoning: This rule is not explicitly stated anywhere that I have seen, but is somewhat obvious and inferred by the lack of other information. In the Dreadful Word example, we would have no idea what spell save DC to even use for confusion if we do not assume it counts as a warlock spell for you and uses your warlock spell save DC. It seems to blatantly assume you know to use your warlock spellcasting information, despite the fact that it's not normally on the warlock spell list. We also, for what it's worth, have a Crawford tweet backing this interpretation up:
@JeremyECrawford If I am a Warlock and I use an invocation to cast a spell that's not on the Warlock list (such as Levitate, Confusion, or Slow) requiring a save, does it use my Warlock spell save DC? Also, can such a spell benefit from Rod of the Pact Keeper?
The spells you cast through the Eldritch Invocations feature are meant to be warlock spells for you. #DnD
2. Are you casting the spell via the Spellcasting/Pact Magic class feature, and the means by which you learned that spell are explicit about which class' it now counts as?
The other part of this to consider is this means that even if you learned confusion via another class (suchQualifying/valid examples:
- A cleric makes use of their Spellcasting class feature and casts a spell that is on their Domain Spells list.
- A bard makes use of their Spellcasting class feature and casts a spell that they learned from the paladin class' spell list via Magical Secrets (like destructive wave).
If yes, then it counts as multiclassing into sorcerer or the like)specified class' spell; cleric Domain Spells say they count as cleric spells for you, this invocation's instance of casting it would still be a warlock spelland bard Magical Secrets explicitly say the spells you learn now count as bard spells for you, so that's what they are.
I imaginewanted to call this would also cover spells from monks' Way of the Four Elements' Elemental Disciplinesrule out separately and explicitly, preventing them from being consideredbut due to be any other class' when cast thatthe way. these features add their associated spells to your class' spell list, it's effectively the same as:
2. The source of the spell specifically states it counts as a particular class'.
This one's a bit obvious. This is for cases like the bard's Magical Secrets or the cleric's Domain Spells, where it is explicitly stated that a learned spell counts as a particular class'. Only bothering listing it here for thoroughness' sake. This rule is generally the overriding exception to:3. TheAre you casting the spell was learned or cast via the Spellcasting/Pact Magic class feature, and you learned the spell from a specific class' spell list. (usually, but not always, your own class')?
This one comes from the [Sage Advice Compendium](http://dnd.wizards.com/articles/sage-advice/sage-advice-compendium)'s official ruling in regards to Magic Initiate:Qualifying/valid examples:
- A sorcerer expends a 3rd level spell slot with the Spellcasting class feature and casts fireball, which they added to their list of spells known from the sorcerer spell list at sorcerer level 5.
- A warlock expends a Pact Magic spell slot to cast arms of Hadar, which they learned via taking the Magic Initiate feat, picking warlock for the associated class, and picking arms of Hadar as the 1st level spell option for the feat.
- A druid expends a 1st level spell slot to cast Tasha's caustic brew, which they obtained from the artificer spell list via the Artificer Initiate feat.
If yes, then whichever class' spell list you learned it off of determines the class the spell belongs to. This is the case you'll hit for 'typical' spellcasting- casting a spell via Spellcasting/Pact Magic that you learned off your class' spell list, as usual.
Reasoning: In the warlock/Magic Initiate example, we know this works because of an official ruling in the Sage Advice Compendium:
If you have spell slots, can you use them to cast the 1st-level spell you learn with the Magic Initiate feat? Yes, but only if the class you pick for the feat is one of your classes. For example, if you pick sorcerer and you are a sorcerer, the Spellcasting feature for that class tells you that you can use your spell slots to cast the sorcerer spells you know, so you can use your spell slots to cast the 1st-level sorcerer spell you learn from Magic Initiate. Similarly, if you are a wizard and pick that class for the feat, you learn a 1st-level wizard spell, which you could add to your spellbook and subsequently prepare.
In short, you must follow your character’s normal spellcasting rules, which determine whether you can expend spell slots on the 1st-level spell you learn from Magic Initiate.
Magic Initiate does not overtly declare the learned spell to count as the class' whose list you are learning it off of. However, this official ruling is statingstates that the spell has to be learned off of your own class' list, or else it does not count as your class'. As such, I feel this ruling is inferringFrom there we can infer that learning a spell off of a particular class' spell list makes it countmeans that that spell counts as that class' (unless otherwise specified, which tiesas in the question #2 case above with that initial quoted tweet from Crawfordbard's Magical Secrets). Otherwise
If this is the case, I imaginewe can also infer that in the answerArtificer Initiate feat example here, the cast of Tasha's caustic brew would state "Yescount as an artificer spell; normally, a druid would not be able to cast an artificer spell with their Spellcasting feature ("The Druid table shows how many spell slots you have to cast your druid spells of 1st level and higher."), but only if the Artificer Initiate feat provides a more specific exception that allows it ("You can also cast the spell using any spell slots you pick is on one of your classes' lists"have.").
This also typically covers spells you've learned the usual way, through the Spellcastingsame reasoning leads into:
4. Does the feature you are using to cast the spell explicitly state what class' spell list the spell is from?
(You could say that anything from #3 is a subset of this scenario, as to cast the spell via Spellcasting/Pact Magic you have to know and/or prepare it first, which generally involves getting it from a class' spell list. The ruling is the same.)
Qualifying/Pact Magic feature.valid examples:
- A druid expends their once-per-long-rest ability to cast arms of Hadar via the Magic Initiate feat (without expending a spell slot); warlock was the chosen class for Magic Initiate.
- An Arcane Trickster rogue uses the once-per-long-rest ability of the Artificer Initiate feat to cast the 1st level spell Tasha's caustic brew without expending a spell slot.
If none of those 3 steps above apply andyes, then it counts as the class whose class spell is still 'classless'list was specified. In the druid with Magic Initiate example, thenarms of Hadar the "a class'sstill counts as a warlock spell list is the list of that class's spells" guideline comes in, and you can choose one of your classesin the Arcane Trickster with that spell on its list to have it countArtificer Initiate example, the Tasha's caustic brew cast counts as that class'an artificer spell. This simply follows from the Sage Advice Compendium ruling interpretation we're using here in #3.
If you've gotten this far without an answer...
ToQualifying/valid examples:
- You are casting a spell via a magic item such as the wand of magic missiles that does not explicitly specify the spell counting as any class' spell.
- You are casting a spell via a non-class feature that makes no reference to a class, such as using a tiefling's Infernal Legacy trait to cast hellish rebuke.
At this point, we've run throughout of what is now considered official rulings to guide us. We're in the wand of magic missile exampleland of Crawford tweets/implications, point 1 doesn't applyand honestly, no one would blame you for simply ruling that spells that haven't met any of the above criteria don't count as it's not being cast via a class feature, it'sany class' spells upon being cast through the generic 'use a magic item' action. Point 2 doesn't applyRemember, as the wand doesn't say it counts as a wizard Crawford tweets are no longer considered official rulings. That said, here's what other guidance we have:
5(?). Is the spell on your class' spell list?
Qualifying/valid examples(or otherwise?) spell. Point 3 may apply if you've learned it from one of your classes:
- An evocation wizard uses a wand of magic missiles to cast magic missile, and uses Empowered Evocation to boost the damage. The wizard does not have magic missile in their spellbook, nor does the wizard have it prepared.
- A Wild Magic sorcerer expends a spell slot to cast disguise self, which they learned via the 1st level illusion spell option as part of the Shadow Touched feat. A Wild Magic Surge triggers off of this casting.
If yes, in which casethen the spell is somewhat locked in to thatcan count as a class spell for your class. If you haven't learned it and point 3 doesn't apply, then Crawford's 'fallback' statement applies, and you may choose to
Reasoning: We have a few tweets as the basis for this. For the wand of magic missiles' spellcast count as any of your classes which example, we have magic missile on their list.
This also syncs up with Crawford's tweets stating that effects that trigger off of 'class spells' can trigger off of wandsa rather straightforward twitter Q&A:
@JeremyECrawford when a wild magic sorcerer uses a wand of magic missiles, can he trigger a Wild Magic Surge?
@TheMaDdi3 Yes.
@JeremyECrawford, 2:57 PM - 9 May 2016
If this is the case, (unless Crawford was making this assumption) then you don't need to actually have learned the spell from your class' spell list to have it count as a class spell for you; it simply being on your class' spell list is enough. This ruling is backed up by a slightly more recent tweet along the same lines:
What ultimately makes something a [class] (wiz/sorc/etc) spell? Is having it on your spell list enough, even if you're not high enough to cast/don't know it/don't cast via Spellcasting? I.E., can a level 1 Sorc Wild Magic Surge off of Luck Blade's wish despite not knowing it yet?
@SymphFan, 4:12 PM - 26 Jun 2018
A class's spell list is the list of that class's spells. #DnD
@JeremyECrawford, 5:57 PM - 26 Jun 2018
While this answer doesn't directly address the portion of the question about Wild Magic Surging off a Luck Blade's wish, between this tweet and the previous one about the wand of magic missiles it certainly seems to confirm the intent is that if the spell is on your class' spell list, then anything that depends on it being a 'class' spell can apply.
The only other note I have to leave is that while I didn't get much into how this all interacts with the multiclassing rules (since those are technically optional), the important rule from there to keep in mind is the following (even if it may have a hole in it):
Each spell you know and prepare is associated with one of your classes, and you use the spellcasting ability of that class when you cast the spell.
(My own emphasis added on the 'one'.)