Magical traps, Illusions and Divination magic

[Friend of the Dork]

Hello guys

In the pathfinder groups I play with we sometimes debate how Magical traps and illusions work with divination magic.

Magical traps are said "a Rogue(and only a Rogue) can detect a magical trap with Search/Perception check. However, being a spell is it not detectable also by a simple detect magic? The only problem with that is that it completely nullifies the Rogue's ability as any spellcaster can use detect magic all the time and discover all (possible) magical traps. Then they can be dealt with by Dispel Magic etc.

The same thing about Illusions: Can you detect the aura of a Invisibility spell and pinpoint it's location with detect magic, or is the illusion spell simply invisible? Is a wizard with a Disguise Self spell easily spotted by the Illusion magic on him?

And at the last, is the Alarm spell counted as a magic trap(thus detectable by Rogues) or just a normal spell that can be detected by detect magic?

I'd appreciate both RAW and RAI responses.

[Friend of the Dork]

Bump!

A day is a long time without an answer on this forum, Is my question not clear enough?

[Lathiira]

You need to parse the quote for rogues slightly differently. Instead of thinking "only rogues can detect a magical trap, with a Perception check", it's actually they're the only ones who can do it via Perception. Except for all those archetypes that gain that ability, of course. Detect magic will reveal magical auras and whatnot as usual, over the course of 3 rounds, and can still miss things if the magical auras get layered on etc.

Detect magic won't tell you the exact spells in use. A wizard with an illusion aura on him might be using disguise self. Or it might be a simulacrum. Or a project image. You'll get different aura strengths potentially, but the spell is detect magic, not "identify every magical effect in existence" magic.

[Ilja]

To a large part, detect magic makes the rogue's ability less useful. However:
1. It takes three rounds to determine type and strength of the auras, before that it's likely to get a lot of false flags in a magic-heavy environment (if there's continual lights around for example).
2. The 1st level spell Magic Aura masks magic items (including traps) for 1 day/level. This can be used to block detect magic, but does not block rogues.
3. I can't remember if this is one of our house rules or part of the core rules, but check if Detect Magic isn't stopped by a thin sheet of lead.

[Friend of the Dork]

Lathiira wrote:

You need to parse the quote for rogues slightly differently. Instead of thinking "only rogues can detect a magical trap, with a Perception check", it's actually they're the only ones who can do it via Perception. Except for all those archetypes that gain that ability, of course. Detect magic will reveal magical auras and whatnot as usual, over the course of 3 rounds, and can still miss things if the magical auras get layered on etc.

Detect magic won't tell you the exact spells in use. A wizard with an illusion aura on him might be using disguise self. Or it might be a simulacrum. Or a project image. You'll get different aura strengths potentially, but the spell is detect magic, not "identify every magical effect in existence" magic.

Yes I think I agree with that interpretation. Detect magic won't tell you that it is a trap, but give you a good hint - last adventure I played in we saw a solid door with an abjuration area on it and clearly avoided the potential trap (got like +8 on Disable device, so disarming magical trap of a spellcaster who advises an evil goddess and lives in Hell sounded like a bad idea).

Ilja wrote:

To a large part, detect magic makes the rogue's ability less useful. However:

1. It takes three rounds to determine type and strength of the auras, before that it's likely to get a lot of false flags in a magic-heavy environment (if there's continual lights around for example).
2. The 1st level spell Magic Aura masks magic items (including traps) for 1 day/level. This can be used to block detect magic, but does not block rogues.
3. I can't remember if this is one of our house rules or part of the core rules, but check if Detect Magic isn't stopped by a thin sheet of lead.

1. Using continual light or other obvious magic to fool them from checking further might work, although if they are careful they will spend 3 rounds before each door etc. to see that the abjuration aura on the door is not the same as the evocation aura from the continual light.

2. It should work, which makes me wonder why this 1st level spell is not ALWAYS a part of every magical trap apart from Glyphs of warding. How much more does a magical trap cost by adding this spell?

A one-shot trap costs 50gp to add a Magic Aura spell. Multiple use trap costs 500gp more - sounds like a no brainer to keep it being detected by a 0th level spell that almost every spellcaster has and uses.

3. It is stopped yes. However, the traps own detection effect might also be blocked by the lead, so not sure if this is bulletproof.

Anyway, thanks for responses, both of you.