Can you react when gear is equipped?
Yes. Equip is an activated ability, so using it goes on the chain and creates a closed state. Opponents can respond during that window with Reaction cards and abilities before the equip resolves.
Cited rules
- 818.1 Equip is an Activated Ability keyword.
- 401.1 Add a Pending Item to the chain representing the Ability that is either being Activated or Triggered. Notably, although this Chain Item will not have a card representing it, this will create a Closed State. See rule 349. Playing Cards for more information.
- 309.1.a Only cards and abilities with the Reaction keyword can be played or activated in a Closed State.