Adept's Insight says:
Noble Adept Feature Adept's Insight
With a mental focus, you enhance the undeniability of your actions.
Encounter Psionic
Free Action Close burst 5
Trigger: You or an ally in the burst makes an attack roll, saving throw, or skill check.
Effect: You add 1 to the triggering roll.
Augment 1
Effect: You instead add 1d4+1 to the triggering roll.
I want to apply it to an attack roll, but only if +1 (or +2, if augmented) would actually help me to overcome the monster's defense. Do I know if the +1 (or +2) bonus would be enough to hit the monster, i.e. can I ask the DM to tell me?
Normally, we announce our attack roll+modifier and the DM says "it hits" or "it misses," and vice versa, the DM announces monsters' attack rolls and we say whether it hits our characters.