Awareness (Fallout Supplement)
From D&D Wiki
You've studied your enemies wisely, and now you know all the signs of their defenses, offensive capabilities and state of health.
Prerequisite: Level 10, Wisdom 10, 10 ranks in Spot
Benefit: As a move action, you can make a DC 20 Spot skill check to learn the HP, Defense, equipped weapon and ammunition count of any character, creature or robot.
Normal: This information is hidden from players.
Special: The Spot skill check must be made per enemy.