Can a rogue use Uncanny Dodge to halve the damage of a Spiritual Weapon?

Question

Can a rogue reduce spirit weapon attacks and spells with Uncanny Dodge?

The answer doesn't seem clear to me, based on the description of the feature.

Answer 1

Yes, Uncanny Dodge applies to spell attacks (but not all damaging spells)

The exact text of Uncanny Dodge is:

Starting at 5th level, when an attacker that you can see hits you with an attack, you can use your reaction to halve the attack’s damage against you.

The only requirements for triggering the ability are that you:

1. Are hit by an attack
2. Can see the person who attacked you
3. Have a reaction to spend

Spell attacks, such as those made by the spiritual weapon spell and others, are still attacks. As the basic rules describe:

If there's ever any question whether something you're doing counts as an attack, the rule is simple: if you're making an attack roll, you're making an attack.

So long as the attacker had to roll to hit you, it is an attack that can be reduced with Uncanny Dodge. However, many damaging spells are not attacks - for instance, magic missile hits automatically without an attack roll, and disintegrate is described as firing a ray at the target but it has the target make a Dex save rather than the caster make an attack roll. In such cases, the spells are not attacks and you cannot use Uncanny Dodge to reduce the incoming damage.

Spiritual Weapon specifically is a little bit of a weird edge case because according to its rules as written, it is the caster that makes an attack against a foe who happens to be adjacent to the weapon:

you can make a melee spell attack against a creature within 5 feet of the weapon

In cases where the rogue can see the summoned weapon but cannot see the actual spellcaster, they technically cannot use Uncanny Dodge to reduce that damage. However, as a DM I'd personally rule that being able to see the weapon counts as being able to see the attacker for this purpose - the obvious theme of spiritual weapon is that it is striking enemies as directed by the caster, so being able to see the weapon move should mean you can see the attack coming and react appropriately.

Answer 2

Yes, unless you can't see the attacker

Uncanny dodge states:

Starting at 5th level, when an attacker that you can see hits you with an attack, you can use your reaction to halve the attack’s damage against you.

So the requirements are that the event in question must be an attack (not some other source of damage like walking into an area effect that deals damage) and the rogue must be able to see the attacker.

The ability does not specify/limit the type of attack that it may be used for. That is, it can be used against any melee / ranged / spell attack. The keyword here is simply "attack."

Spiritual Weapon's description states in part:

When you cast the spell, you can make a melee spell attack against a creature within 5 feet of the weapon. [...]

As a bonus action on your turn, you can move the weapon up to 20 feet and repeat the attack against a creature within 5 feet of it.

The Spiritual Weapon spell grants its caster the ability to make attacks. This satisfies the first of Uncanny Dodge's two requirements. This leaves the requirement that the Rogue see the attacker. It's important to note that the attacker is not the conjured spiritual weapon but the caster.

This is an important caveat because it is possible that there is not direct line of sight between the Rogue and the caster of the Spiritual Weapon. In such an instance, the caster could be subject to the rule on attacking an unseen target. If this is the case, it would impose disadvantage on the attack but not prevent it. The upshot is that, because the rogue does not see the attacker, it would not be able to use Uncanny Dodge.

For the Rogue to be able to use Uncanny Dodge, the caster of Spiritual Weapon would need to be seen.

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That said, I wholeheartedly agree with Carcer's answer that a DM could very reasonably rule that seeing the Spiritual Weapon itself is sufficient to allow the use of Uncanny Dodge. Spiritual Weapon is kind of a weird spell and, outside of a strict reading of the rules, it's hard to reconcile how the visibility of the caster is more relevant than the immediate presence of the weapon itself.

Answer 3

Yes. Uncanny Dodge applies to spell attacks as well.

The rogue feature Uncanny Dodge is valid for all attacks.

Starting at 5th level, when an attacker that you can see hits you with an attack, you can use your reaction to halve the attack’s damage against you.

So long as the attacker who cast spiritual weapon is visible to the rogue the feature is valid as spiritual weapon explicitly uses a "melee spell attack".