Does the Artillerist Artificer add their spellcasting damage mod to attacks using their Force Balista?

Question

An artillerist artificer gains use of an "eldritch cannon" as part of the subclass' abilities. It has several modes, one of which is force ballista, which allows the artillerist to fire it as a bonus action to do the following:

Make a ranged spell attack, originating from the cannon, at one creature or object within 120 feet of it. On a hit, the target takes 2d8 force damage, and if the target is a creature, it is pushed up to 5 feet away from the cannon.

When DnD Beyond shows this attack, it shows the spellcaster's attack modifier being applied to damage, but the ability is unclear as to whether this ability should be applied, and we know that DnD Beyond makes mistakes. Should this modifier be applied to damage?

Answer 1

No

If the description of the ability doesn't say that the ability modifier should be applied to the damage, then it isn't.

In the Damage Rolls section of the Players Handbook (or Basic Rules), it states:

When attacking with a weapon, you add your ability modifier—the same modifier used for the attack roll—to the damage. A spell tells you which dice to roll for damage and whether to add any modifiers.

So for weapons we always add the ability modifiers, but for a spell we only do when the spell descriptions say we should.

Although it's not a spell, the Force Ballista calls for a ranged spell attack, so it's more likely that it falls under the rules for spell attack rolls and spell damage.

As an example of a spell which does add the ability modifier to its damage, we have the warlock's Eldritch Blast when combined with the Agonizing Blast eldritch invocation, which states:

When you cast eldritch blast, add your Charisma modifier to the damage it deals on a hit.

So in this example it explicitly states that you add your Charisma modifier to the damage. The Force Ballista does not say anything about it, so you cannot add your spell ability modifier, unless another ability states otherwise, but I haven't found any ability in the artificer class that would allow it.