[RPG] way to detect an NPC’s class without them knowing that I’m detecting it

classdnd-5enpc

The description of the detect thoughts spell says that when attempting to probe deeper into a target's mind (which I assume would be required to detect their class):

the target knows that you are probing into its mind

I want to know whether there is any way at all to determine an NPC's class without them knowing in 5e, e.g. by adding other effects from spells or magic items, or by a different tactic entirely.

I would be OK with answers that have limits such as detecting some classes but not all.

Best Answer

There are no rules that would explicitly provide a way to do this, because D&D doesn’t want to make a stand on whether or not classes are things that characters are aware of and know themselves. Some things—paladin oaths, warlock patrons, etc.—are pretty explicit and obvious, but others, particularly fighter and rogue are very generic and can lend themselves to a wide variety of characters, occupations, and fighting styles. There is no particular reason why they would necessarily see any commonality between them.

Which therefore means that class may not be a thing to know. That may, depending on your campaign, be purely metagame information. It’s entirely plausible, in fact, that even things like oaths and pacts are not as neat and consistent as laid out in the books, but rather more unique to the individuals involved. It is very reasonable for, say, a sorcerer/warlock to say that all of their power comes from the patron, just that it’s a different sort of pact than a pure warlock has. And so on and so forth.

Since D&D doesn’t want to dictate how any given table handles this, they cannot write mechanics that rely on it being “real” in-character information, so no such detection spell could be written.1 If classes are real, known concepts within your campaign, you will have to ask your DM for details on how you can know and recognize them in character.

  1. This applies to a lot of things in D&D, and always has, though 5e is arguably trying to go farther with it than other editions. However, they aren’t doing so perfectly—while they often say they support a variety of playstyles, they sometimes seem to forget that and write mechanics that presuppose one particular style. But this is one particular case where they haven’t done that, and personally I suspect they won’t.