What makes a spell being cast considered to be a {class} spell?

Question

My understanding is that when a spell is known or prepared via one of your class features, or if you cast it via a class feature, it's considered a "class spell" (sorcerer spell, cleric spell, etc.) for you. If you cast it via some method outside your class (items, etc.), it isn't considered a spell from your class.

For clarity, some class features care about whether or not a spell is a 'class' spell (emphasis mine):

• Wild Magic Surge for Wild Magic sorcerers can only trigger "[...] immediately after you cast a sorcerer spell [...]".

• Overchannel for School of Evocation wizards can only be used "when you cast a wizard spell [...]"

• Empowered Evocation for School of Evocation wizards can also only be used on "[...] any wizard evocation spell you cast".

• Rod of the pact keeper gives a bonus "[...] to the saving throw DCs of your warlock spells".

Contrast with a feature like Blessed Healer for Life Domain clerics that just use the language of "When you cast a spell [...]", and you'll see why I believe there's an important distinction as to whether or not a spell instance is a 'class' spell.

However, comments on this answer made me question where my understanding of what makes a spell instance a 'class' spell comes from, and I'm not sure of a concise spot that explains it. What are the rules that govern what is or is not considered a class spell when cast?

Of particular concern is whether or not a spell is, in all instances, a class spell once you've obtained it from your class. For example, if you were a wizard that had magic missile both prepared and in your spellbook, would any instance of magic missile you cast be considered a wizard spell, even if it was cast by way of, say, a wand of magic missile?

Answer 1

A spell is considered a Class Spell if it's listed in the class' spell list

While not explicitly defined this way, there is evidence of it being implied:

Domain Spells

[...] If you have a domain spell that doesn't appear on the cleric spell list, the spell is nonetheless a cleric spell for you.

Circle Spells

[...] If you gain access to a spell that doesn't appear on the druid spell list, the spell is nonetheless a druid spell for you.

With how the above features are worded, you may infer that any spell that is not on the class' spell list in PHB 207-211, is not a class spell, because the only way to add a spell to your class spell list is through similar features as above. And that, through inversion, any spell in a class' spell list is a class spell.

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Jeremy Crawford weighs in with a tweet here:

A class's spell list is the list of that class's spells. #DnD

Answer 2

The common understanding is that if the source of the spell is a class feature (Spell Casting, Domain, Pact Patron, etc.), it is a class spell. But looking at the books, let's see what we find.

Common RAW Wording in the PHB

Typically this language appears when talking about learning spells rather than casting them. Like in Eldritch Knights' or Arcane Tricksters' class feature uses the two phrases interchangeably.

When you reach 3rd level, you augment your martial prowess with the ability to cast spells. See chapter 10 for the general rules of spellcasting and chapter 11 for the wizard spell list.

Cantrips. You learn two cantrips of your choice from the wizard spell list. You learn an additional wizard cantrip of your choice at 10th leveI.

Followed by:

The Spells Known column of the Eldritch Knight Spellcasting table shows when you learn more wizard spells of 1st level or higher.

Multiclassing

When multiclassing you are supposed to keep track of which spell list they are from to know which spell casting stats to use, and there you run into questions about when is it "Wizard Spell" or "Ranger Spell" -- but that too is short hand for "spell you know from the Spell Casting feature from the Wizard Spell List".

For the spellcasting feature it is easy:

You determine what spells you know and can prepare for each class individually, as if you were a single-classed member of that class. ... 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.

Items

Searching the DMG, I only find "Wizard spell" in Epic boons and not in the item list. Though, the Rod of the Pact Keeper does refer to Warlock Spells, and that is slightly more clearly defined because of uniqueness of Warlock Spell Slots. Here though, you're not casting from the Rod itself. I suppose you could wonder if you can use that +1 on a wand of a warlock spell, and I think the answer here is clearly "no".

Wand of Magic Missile

I would have said that a wizard who casts from a Wand of Magic Missiles wouldn't be casting a Wizard spell as it isn't using a spell slot, isn't a spell from the wizard spell book at that moment, and isn't using the Wizard's Spell DC or Spell Attack stats -- As far I can tell from the text above.

However, that appears to be incorrect. Being on the class list is enough to count as a class spell (which fits with the PHB section above), as evidenced by this answer from Crawford on Wild Magic Surges:

Metamagic works w/ any spells that sorcerers cast. Wild Magic Surge can work w/ any sorcerer spell they cast. #DnD

https://twitter.com/JeremyECrawford/status/652539767821766656

Answer 3

To provide an answer to this, a lot of rules need to be inferred from context, the Sage Advice compendium, and RAI tweets from Crawford.

My recommendation would be to go down the following list of questions in order until you get an applicable answer, then stop. I'll do my best to explain why under each question, and give a (very much non-exhaustive) example of a case that fits the question.

(Note that I'm attempting to list generalized rules; there may be features/abilities/items/etc. that are explicit, blatant exceptions to these.)

1. Is the spell being cast directly through one of your class features that is not Spellcasting/Pact Magic?

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:

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@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?

@Bloodcinder, 5:19 AM - 21 Feb 2019

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The spells you cast through the Eldritch Invocations feature are meant to be warlock spells for you. #DnD

@JeremyECrawford, 5:18 PM - 21 Feb 2019

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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?

Qualifying/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 the specified class' spell; cleric Domain Spells say they count as cleric spells for you, and bard Magical Secrets explicitly say the spells you learn now count as bard spells for you, so that's what they are.

I wanted to call this rule out separately and explicitly, but due to the way these features add their associated spells to your class' spell list, it's effectively the same as:

3. Are you casting the spell 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')?

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 states that the spell has to be learned off of your own class' list, or else it does not count as your class'. From there we can infer that learning a spell off of a class' spell list means that that spell counts as that class' (unless otherwise specified, as in the question #2 case above with bard's Magical Secrets).

If this is the case, we can also infer that in the Artificer Initiate feat example here, the cast of Tasha's caustic brew would count 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 the Artificer Initiate feat provides a more specific exception that allows it ("You can also cast the spell using any spell slots you have.").

This same 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/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 yes, then it counts as the class whose class spell list was specified. In the druid with Magic Initiate example, arms of Hadar still counts as a warlock spell, and in the Arcane Trickster with Artificer Initiate example, the Tasha's caustic brew cast counts as 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...

Qualifying/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 out of what is now considered official rulings to guide us. We're in the land of Crawford tweets/implications, and honestly, no one would blame you for simply ruling that spells that haven't met any of the above criteria don't count as any class' spells upon being cast. Remember, 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(?):

• 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, then the spell can count as a class spell for your class.

Reasoning: We have a few tweets as the basis for this. For the wand of magic missiles example, we have a rather straightforward twitter Q&A:

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@JeremyECrawford when a wild magic sorcerer uses a wand of magic missiles, can he trigger a Wild Magic Surge?

@TheMaDdi3, 3:18 AM - 5 May 2016

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@TheMaDdi3 Yes.

@JeremyECrawford, 2:57 PM - 9 May 2016

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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:

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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

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A class's spell list is the list of that class's spells. #DnD

@JeremyECrawford, 5:57 PM - 26 Jun 2018

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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'.)

Answer 4

Depends on what feature gave you the spell

This is made clear in the Multiclassing rules:

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. (PHB 164)

In other words, a wizard spell is a spell granted by a wizard class feature (or one that explicitly says so), as that is the feature that lets you learn and prepare it.

Adding a spell to your list and making it a class spell are different things, apparent from the wording of features like this:

If you have a domain spell that doesn't appear on the cleric spell list, the spell is nonetheless a cleric spell for you. (PHB 58)

Note that this does not add the spell to your list, yet states that it is a class spell. So domain spells would be an example of spells that are not on your list, yet are cleric spells (for you). They are cleric spells, because a cleric feature granted them.

Magic items

As these spells are not granted by a class feature, nor do you know or prepare them with those features, they are not class spells of any class.

Answer 5

Using the Wand of Magic Missiles as the touch-point, how is that Wand created? Probably not specified, but it seems logical that someone with the ability to cast Magic Missile personally used their magic to create the wand and used their own ability to learn and cast Magic Missile to give the wand the ability to cast a Magic Missile spell itself. Thus, through the creating wizards abilities, the wand has become a caster in it's own right, and it is casting a wizard class spell.

Anything that takes effect because a wizard spell was cast, would be triggered by the use of the wand, because the wand has cast a wizard class spell. For example, if a hallway in Athena's temple has a trap that triggers when a wizard spell is cast (after all, what temple would want wizards running around inside casting spells?) the trap would be triggered by the use of the wand, even if it was used by a fighter, or, quite unfortunately, even if used by one of the temple's own clerics in defense of the temple. The flip side is that the caster is the wand, not the wielder. Specifically with regards to the Evocation Wizard, it seems logical that the wizard didn't cast the spell, even if the wizard has the spell available to cast at that moment, therefore it cannot be Empowered or Overchanneled by the wizard. (Maybe a very advanced Evocation Wizard could find a way to create a Wand of Overchanneled Magic Missiles!)

An alternative applies for other types of items, however. Scrolls, especially Spell Scrolls, being a good example here. If the item gives the ability "to the wielder" to cast a spell, then it is the character casting the spell, not the item. The effect triggering applies, just as in the Wand of Magic Missiles above. The abilities of the caster can also, now, be applied to it. Say a wizard has a Magic Missile Scroll and reads it, thus "casting" it, then the Empowered Evocation or Evocation Overchannel could be applied to the use of the spell from the scroll. The key difference between the two situations is that, in the first case, the item is casting the spell, and in the second case the user is casting the spell, with an ability bestowed by the item.

As an easy, though not certain, method of deciding whether it is the item or the user that is casting the spell, consider the manner of determining its effect. If the effects, such as damage amount, are linked to the user (level, intelligence, wisdom, etc.), then you can likely consider the caster to be the user. If the effects, such as damage amount, are fixed, then you can probably consider the caster to be the item.

Answer 6

Some clear cases, some not

There are several possible ways to resolve this. There is a clear, direct answer: Any spell you cast that is on your class spell list counts as a spell of that class. This has the advantages of being simple, being found in multiple places all supporting each other, and being a response directed at the question itself. It has the disadvantage of being largely based on (now unofficial) tweets from Jeremy Crawford. I choose not to follow that path for reasons other than it being unofficial, per se. First, this is a complex question and I don't think all the nuances and caveats lend themselves to explanation within a tweet character limit. Second, I am uncomfortable with one logical conclusion that follows - an individual spell you cast that is on two different spell lists of yours is then simultaneously a spell of both of those classes. And third, it contradicts what is an official Sage Advice ruling (see below). I think unofficial answers (tweets) have a valuable role in clarifying things when official answers aren't forthcoming, but I hesitate to accept them when they contradict what is official.

Another way to resolve this is to look at what is actually within the the text of official sources such as the PHB and Sage Advice. Unfortunately, this approach relies on interpreting passages that are not explicitly directed at the question itself ('what makes a spell of a certain class?'), and interpretations can vary.

In particular, the passage that I find most helpful is in the rules on Multiclassing, which are themselves optional. I understand the arguments of those who would apply this passage narrowly ('this section about spells is only for PCs who multiclass, and only if you agree to that option'), but I choose to interpret it broadly ('this optional section illustrates a larger point about how spells work that is true across the core system'). My choice is undeniably biased toward utility - I find a speculative principle that I can actually use better than the interpretation that there is no clear answer to the larger question. The latter might be true, but it is not particularly helpful, and now, six years after publication of the PHB, after numerous errata and Sage Advice clarifications, and after two large presentations of new rules (XGtE and TCoE), at least one of which deliberately clarified questions about timing, sleeping, AoE on a grid, etc., it seems likely that WoTC either considers this issue settled or has no interest in addressing it.

Here is the passage in full from the Multiclassing Rules:

Your capacity for spellcasting depends partly on your combined levels in all your spellcasting classes and partly on your individual levels in those classes. Once you have the Spellcasting feature from more than one class, use the rules below. If you multiclass but have the Spellcasting feature from only one class, you follow the rules as described in that class.
Spells Known and Prepared. You determine what spells you know and can prepare for each class individually, as if you were a single-classed member of that class. If you are a ranger 4/wizard 3, for example, you know three 1st-level ranger spells based on your levels in the ranger class. As 3rd-level wizard, you know three wizard cantrips, and your spellbook contains ten [sic] wizard spells, two of which (the two you gained when you reached 3rd level as a wizard) can be 2nd-level spells. If your Intelligence is 16, you can prepare six wizard spells from your spellbook.
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. Similarly, a spellcasting focus, such as a holy symbol, can be used only for the spells from the class associated with that focus.

Objection: This section is optional, and specifically says it is to be used only "once you have the Spellcasting feature from more than one class".
Response: Yes, but it also distinguishes between rules (like those about spells known and prepared) that are true "as if you were a single-classed member of that class" and rules (like those about total spell slots) that apply only when you have multiple Spellcasting classes. I don't think it is unreasonable to believe that the principles it clarifies 'as if you were single classed' also apply to when you actually are single-classed. As for it being optional, many of the times the greater question of 'how do you know when a spell is a class spell' actually comes up is when attempting to adjudicate other optional features, like Feats. I will take guidance where I can find it.

If we accept that the passage is establishing a general principle, how do we rule?

In what follows I am assuming that by "each spell you know and prepare is associated with one of your classes" means that:
If a feature that allows you to know a spell can be tied to a specific class, that spell counts as being of that class.
Indeed, what else could it mean that would not be redundant or a tautology? What other kind of association is worth mentioning?

Spells you know on your list because of your class's Spellcasting ability

Class spells are spells off the class spell list that you know because you are that class (you have the Spellcasting ability by virtue of you being in that class).

For example; "Sorcerer: Spellcasting" (PHB 101; emphasis mine)

Spell Slots The Sorcerer table shows how many spell slots you have to cast your spells of 1st level and higher. To cast one of these sorcerer spells, you must expend a slot of the spell’s level or higher...
Spells Known of 1st Level and Higher The Spells Known column of the Sorcerer table shows when you learn more sorcerer spells of your choice...Additionally, when you gain a level in this class, you can choose one of the sorcerer spells you know and replace it with another spell from the sorcerer spell list, which also must be of a level for which you have spell slots.

Notice the subtle distinction between "sorcerer spells" and a "spell from the sorcerer spell list". A spell becomes a sorcerer spell for you when you know it. Just being on the sorcerer spell list is not enough; it does not become a sorcerer spell for you until you know it.

Spells you gain access to through a class feature but not through the Spellcasting feature of that class

If something besides your class Spellcasting feature grants you the ability to cast a spell, typically it will tell you what class of spell it is.

For example, the Cleric's Domain feature (PHB 58):

If you have a domain spell that doesn’t appear on the cleric spell list, the spell is nonetheless a cleric spell for you.

Here, although the spell does not appear on the cleric spell list, and in fact appears on another spell list, it is still a cleric spell because the feature granting it to you says it is (I argue that the underlying principle is that it is a cleric spell because knowledge of the spell is granted through a cleric class feature, but grant that it does not say that explicitly). Thus, if a specific class feature gives you a spell, it would be a spell of that class if the feature said it was (see also the Druid's Circle spells and the Bard's Magical Secrets).

Sometimes a class feature gives you a spell but explicitly says it is not of that class:

The Spells Known column of the Eldritch Knight Spellcasting table shows when you learn more wizard spells of 1st level or higher.

In this case, the spells you know as an Eldritch Knight are wizard spells, not fighter spells.

Spells you know because of general (non-racial) Feats

You might also know a spell through the optional rule of feats, which are not a class feature. However, these will still typically imply what kind of spell you are getting.

"Feats: Magic Initiate" (PHB 168)

Choose a class: bard, cleric, druid, sorcerer, warlock, or wizard. You learn two cantrips of your choice from that class’s spell list. In addition, choose one 1st-level spell from that same list. You learn that spell and can cast it at its lowest level. Once you cast it, you must finish a long rest before you can cast it again. Your spellcasting ability for these spells depends on the class you chose: Charisma for bard, sorcerer, or warlock; Wisdom for cleric or druid; or Intelligence for wizard.

This feat stops short of saying the spells you learn are spells of the class whose list you chose. Fortunately there is a Sage Advice Compendium that more explicitly addresses Magic Initiate:

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.

Here, we are told explicitly that a spell counts as a sorcerer spell not because you knew it through a sorcerer class feature, but because you deliberately learned it from the sorcerer spell class list. Had the same spell also been on another class list as well as that of the sorcerer, and you learned it through Magic Initiate as the other class, it would not count as a sorcerer spell. This is the most explicit contradiction of the Crawford tweets. See also the "Ritual Caster" feat, and this question about sorcerers triggering wild magic surges when using the Magic Initiate feat.

Spells you know through a racial feat

Some racial feats tell you the class of the spells they are granting.
"Wood Elf Magic" in XGtE

You learn the magic of the primeval woods, which are revered and protected by your people. You learn one druid cantrip of your choice. You also learn the longstrider and pass without trace spells, each of which you can cast once without expending a spell slot. You regain the ability to cast these two spells in this way when you finish a long rest. Wisdom is your spellcasting ability for all three spells.

Others do not.
"Drow High Magic" in XGtE

You learn more of the magic typical of dark elves. You learn the detect magic spell and can cast it at will, without expending a spell slot. You also learn levitate and dispel magic, each of which you can cast once without expending a spell slot. You regain the ability to cast those two spells in this way when you finish a long rest. Charisma is your spellcasting ability for all three spells.

When the Feat tells you the class explicitly, those spells count as a spell of that class. When it does not, the spell you know is not associated with a class. See also this question about the spells granted by racial feats.

Spells you have access to through magic items

Magic items that grant you the ability to cast spells do not typically tell you what kind of spells they are, although it is clear that it is you who are casting the spell, not the item, which is important if you are interacting with a feature that says 'when you cast a spell' or 'when you cast a {class} spell'.

"Activating an Item; Spells" (DMG 141)

Some magic items allow the user to cast a spell from the item...A magic item, such as certain staffs, may require you to use your own spellcasting ability when you cast a spell from the item. If you have more than one spellcasting ability, you choose which one to use with the item.

Magic items also typically say "you cast", "you can cast", etc in their descriptions. However, they do not usually say that you 'learn' or 'know' a spell, which is in clear contrast to the language used with feats.

Based on this, I would say that if the magic item allows you to cast a spell that you do not know, it is not a class spell. However, if the spell it is allowing you to cast is one that you already know, then you are casting a spell that you know from a specific class, and thus it is a spell of that class.

See also this question about sorcerers triggering wild magic surges when casting putatively sorcerer spells from magic items.

What if you know a spell through more than one means?

If you are multiclassed and have access to a spell from another class that is also on the sorcerer spell list, for example, you still can't cast it as a sorcerer unless you know it through being a sorcerer ("Each spell you know and prepare is associated with one of your classes").

But if you know the spell both as a sorcerer and as another class, is it a sorcerer spell? I would say that you make that decision at the moment you cast it, based on the multiclassing rules: "you use the spellcasting ability of that class when you cast the spell".

I realize that 'your spellcasting ability' (ie, Charisma) is not 'your ability to use Spellcasting' (ie, a class feature). But the precedent of, when a spell could be sourced from multiple classes, choosing the spellcasting ability at the time of casting seems a clear enough proxy for the class of the spell to me.

(See also this question)

In conclusion, I would say that
Any spell on a class spell list that you know from being that class is a class spell, if you choose to cast it as such.

If a feature allows you to know a spell and explicitly references a class, the spell can also be of that class, if you are of that class and you choose to cast it as such.

Answer 7

A spell you cast is a class spell if:

1. You prepared it using the rules for preparing spells for a particular class and then cast it using a spell slot

2. You cast it as a ritual using the ritual casting rules for a specific class.

3. You cast the spell using a class feature eg. Warlock invocations and mystic arcanum or spell mastery spells for wizard.

Casting using a wand or scroll or other magical item? Not a class spell.

If you have the spell prepared from more than one class then you choose when you cast it which class you are using and it is a class spell for that particular class.