Do the Gloves of Soul Catching heal HP equal to only the damage from the item, or does it include any other force damage from the attack as well?

Question

The description of the Gloves of Soul Catching state, in part (Candlekeep Mysteries, p. 169; emphasis mine):

After making a successful unarmed strike while wearing these gloves, you can use the gloves to deal an extra 2d10 force damage to the target, and you regain a number of hit points equal to the force damage dealt. [...]

Based on this wording, I have 2 interpretations on the number of hit points you regain from this ability:

1. Only the damage from this item: You regain an amount of HP equal to the 2d10 force damage dealt by this particular item.
2. All force damage dealt for this attack: You regain health based on the total amount of force damage dealt as part of the same attack (the sum of 2d10 force damage dealt by this particular item plus any other force damage that was combined with this attack).

An example of the latter would be the Way of the Astral Self monk, where their attacks dealt using the Arms of the Astral Self feature would also do force damage. Does the amount healed by the gloves include this damage along with the 2d10 extra force damage dealt due to the item?

Answer 1

All force damage for this attack.

The phrase “equal to the force damage dealt” has an implied “by the attack”, since that is what is dealing damage here. So to determine the hit points regained, after making the attack and dealing damage, we ask the question “how much force damage did I deal?” The feature description does not discriminate, it only cares about the force damage dealt by the attack. If you have methods of dealing additional force damage with the attack, it is counted as well.

The description could very easily have made it clear that only the additional force damage from the gloves counted by saying:

After making a successful unarmed strike while wearing these gloves, you can use the gloves to deal an extra 2d10 force damage to the target, and you regain a number of hit points equal to the [extra] force damage [the gloves] dealt.

The inclusion of the words “extra” and “the gloves” would make it clear that only the extra force damage from the gloves counts. We even have an example of another magic item doing exactly this. The Crystal Blade from Fizban’s Treasury of Dragons says:

This magic sword’s blade is fashioned from a horn or spine from a crystal dragon. When you hit with an attack roll using this sword, the target takes an extra 1d8 radiant damage.

The sword has 3 charges and regains 1d3 expended charges daily at dawn. When you hit a creature with an attack roll using the sword, you can expend 1 charge to regain a number of hit points equal to the extra radiant damage the sword dealt.

Answer 2

Yes, it’s one or the other

As you spotted, the wording is ambiguous and supports either interpretation. Therefore, it’s up to the DM.