The question has come up in one of my chats, and I could not find an answer after a search of the Pathfinder Roleplaying Game Core Rulebook and Bestiary for 'precise' or 'lifesense'.
Aiudara wraiths (Pathfinder 150: Broken Promises) and various other undead (such as the Bestiary's astradaemon, dullahan, nosoi, morrigna, and wraith) have an ability called lifesense, often with a listed range of 60 feet.
The general entry from the Ability Glossary in the Bestiary notes, of lifesense,
Lifesense allows a monster to sense the vital essence of living and undead creatures within the listed range. The sense can distinguish between the positive energy animating living creatures and the negative energy animating undead creatures, much as sight distinguishes colors.
Meanwhile, the nosoi and morrigna psychopomps and the basic wraith call out in their statblock,
Lifesense (divination, divine): [Wraiths sense/A psychopomp senses] the vital essence of living and undead creatures within the listed range.
... the Aiudara wraith makes no such mention. Neither of the definitions that actually exist offer any insight into how to actually use the ability in play, though, where the rest of the game takes great care to distinguish between precise and imprecise senses.
Is lifesense precise or imprecise, and where would I turn for the general rule covering this situation?