Often confusion arises when the Antimagic Field spell is used, an Armor of Invulnerability is worn, or the Beholder's anti-magic ray is employed, whether a given character's ability will still function.
The spell does give you some guidelines on how to adjudicate the effects of the loss of magic but says very little about how to determine what is affected.
In short, how do I tell if an ability is magical?
Until recently, the answer has been very much the province of the DM's judgement. Some things are very obvious, like a fireball or a magic missile. Some things are not, like ki-powered effects or a dragon's flight.
Wizards of the Coast has released a very easy checklist to determine the difference, included in the Sage Advice Compendium of official rulings.
Within the worlds of Dungeons and Dragons, there are two types of magic:
the background magic that is part of the D&D multiverse’s physics and the physiology of many D&D creatures
the concentrated magical energy that is contained in a magic item or channeled to create a spell or other focused magical effect
Effects that cancel, dispel or nullify magic are concerned only with the second kind of magic. The first is just assumed to be part of the natural physical laws that allow a fantasy world to exist. But again, how to tell the difference? The document gives us a test:
Is it a magic item?
Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?
Is it a spell attack?
Is it fueled by the use of spell slots?
Does its description say it’s magical?
If any one of these questions can be answer "yes", then the effect, ability or item is magical for the purposes of being affected by magic cancelling effects.
To use the examples given above:
Fireball: Yes, it is explicitly a spell.
Magic Missile: Yes, it is explicitly a spell.
Dragon flight: No. It is not a magic item, a spell, or duplicate the action of a spell. It is not a spell attack, or fueled by spell slots. And finally, nowhere in its description is the word "magic" or "magical" used.
Ki powers: Sometimes. Although ki itself is described as magical, the wording is ambiguous, resembling the language used to describe things like dragon flight: "energy [of ki] is an element of the magic that suffuses the multiverse". Some ki powered abilities use the word magical in their description. So although you could use ki to empower flurry of blows within an antimagic field, you could not use Ki Empowered Strikes to any effect since the description says "your unarmed strikes count as magical" (this is clarified and confirmed by Dragon Talk Sage Advice podcast of 10/19/17 at the 29:00 mark)
A few more commonly encountered problem abilities:
Paladin's Divine Smites: Yes, they are fueled by the expenditure of spell slots. Improved Divine Smite appears to be non-magical however, since it fails to meet any of the criteria. Perhaps the paladin is now so pure and devoted to his oath, the he or she is tapping into that other kind of magic. (Devoted question)
The Portent and Third Eye abilities of the Divination wizard: No, they do not meet any of the criteria. It must be assumed that they are natural abilities based on a heightened level of awareness possible within a fantasy universe.
While this question focuses on character abilities, I will expand my answer to abilities outside of what a character has. Particularly abilities, or effects from items.
The sage advice compendium is a compendium of official rulings. It provides a test for determining whether a game feature is magical
Is it a magic item?
Is it a spell? Or does it let you create the effects of a spell that’s mentioned in its description?
Is it a spell attack?
Is it fueled by the use of spell slots?
Does its description say it’s magical?
According to the sage advice compendium, if a game feature meets any of these points, it is magical. The compendium then explains a situation where none of these points are met, and concludes that the feature is not magical; so, even if it isn't explicitly stated, it is implied that if these points aren't met, then the feature should be considered not magical.
With that said, lets add a list of abilities that come from items which are not considered magical:
- "You can expend 1 to 3 Charges as an action. For every charge you expend, you launch a glowing mote of light from the ring at a point you can see within 60 feet of you. Each creature within a 15-foot cube originating from that point is showered in sparks and must make a DC 15 Dexterity saving throw. taking 5d4 fire damage on a failed save, or half as much damage on a successful one.
This ability is not magical, the ability is not a magic item, it is not a spell, it doesn't make a spell attack, it isn't fueled by the use of spell slots, its description doesn't say it is magical. This ability could extend into an anti-magic field while the item is outside.
Chime of opening, I'll spare the text of what it does, it is a magical item itself, its ability is not a magic item, nor does it meet any of the other points, so it is not magical.
Horn of silent alarm, another magical item with a non-magical effect.
Devastation orb, magic item, but 3 of the 4 elemental orbs' effects don't check any of the boxes, and thus using the SA compendium, are not magical effects, and would apparently reach into an anti-magic zone.
every item ability that doesn't specify it allows you to cast a spell, create the effect of a spell, or make a magic attack. There isn't a single magic item I could find that has an ability that is fueled by the use of spell slots, or says it is magical in its description, and the magic items' effects are not themselves magic items. Thus every ability from a magical item is not a magical ability unless the ability is to cast a spell. Basically it is rare for a magical item to have a magical ability
Disclaimer: As I have pointed out, following the SA compendium, rarely do magic items have magical abilities or effects. Every time I have pointed this out, however, I have gotten a lot of flak from the community I have pointed it out to. I myself have the opinion that what I have pointed out is indeed not RAI, even though it is the official ruling.
There is strong evidence that Jeremy Crawford doesn't rule this way (even though he technically wrote the sage advice compendium). For example, here is a tweet which say the following:
Light from any magical source can illuminate the area of a darkness spell, but the darkness spell can dispel light created by a spell of 2nd level or lower, not light created by a non-spell.
In this tweet JC's wording would indicate that light from a magical source would illuminate the darkness spell, this would require that the light is magical. A magic item giving off light would make it a source of the light, it is a magic item so it passes the compendium test for being magical, so it is a magical source. Thus using JC's wording from this tweet, any light from any magical item is magical light, even though almost all light from magic items would fail the Sage Advice Compendium Test.
Using this tweet as the basis, if any light from any magical source is considered magical I think we can add a new qualifier for being magical to the sage advice compendium. If an effect comes from a magical source, that is a magical effect.
