Detecting Spell Loadout

[Palanan]

Power Sight is a Drd 1 spell which allows you to determine the HD of a target creature.

Is there a similar spell which allows you to learn what spells a creature currently has memorized?

[Doctor Despair]

I could see an argument for Detect Thoughts providing that information if coupled with probing questions, or if you used it during spell preparation. Probe Thoughts would probably work.

[daremetoidareyo]

Vatic gaze in phb2

[Palanan]

Originally Posted by daremetoidareyo
Vatic gaze in phb2

Good catch, thanks. It looks like this only provides information on the highest-level spells prepared. Is there anything that could provide the same information for lower-level spells?

[Psyren]

Arcane Sight tells you the strength (level) of their strongest available spell(s), but doesn't specify what those are, nor their entire loadout.

You could get this information indirectly from divinations like Mind Probe (simply ask them what spells they know or what they have prepared that day) or Contact Other Plane/Commune (you'll need to word your questions carefully because most answers will be yes/no.) Neither is foolproof however.

[Doctor Despair]

Technically you could spy on a character for a day, or send hirelings or summons to go fight with the target while you watch from a safe distance with divinations, find out what spells they have, and Teleport Through Time to the beginning of the day.

Edit:
In equally unhelpful techniques, if you can get divine ranks and the Magic or Secrets portfolio, your portfolio sense should give you everyone's spells (in the future or past for X months if you have enough ranks)

[Zaq]

It's not a spell, but a spellthief gains Discover Spells at 13th level, which lets them automatically know all spells a target can cast that are of the same level of the spell that the spellthief just stole from the target.

[Palanan]

I appreciate the suggestions. Sounds like there isn't a single spell or ability that does exactly what I want.

Power Sight is first level, but it's a pretty basic spell. Something that tells you every spell someone has prepared would be more advanced. About what level should that spell be? And how would it scale with caster level? Perhaps as caster level increases, prepared spells at successively higher levels can be identified?

[Psyren]

I found one that's a bit closer to what you want - Spell Gauge from Inner Sea Gods. It starts from the lower levels and goes up, but it does have a ceiling. If your goal is to research/homebrew a stronger variant, this might be a starting point.

[Palanan]

Excellent find, thank you. I'm surprised it's such a low-level spell.

What level would be appropriate for a similar spell that reveals 5th-9th level spells on a target creature?

[daremetoidareyo]

Excellent find, thank you. I'm surprised it's such a low-level spell.

What level would be appropriate for a similar spell that reveals 5th-9th level spells on a target creature?

Probably would be two spells: a fourth or fifth level one that works up to 7th level and a greater one at level 7 or 8 that reveals all spells. Probably throw a condition on the target for each. Dazed for the low level one and stunned on the higher level one with a failed save limiting it to dazed.

[Psyren]

Excellent find, thank you. I'm surprised it's such a low-level spell.

What level would be appropriate for a similar spell that reveals 5th-9th level spells on a target creature?

Comparing to similar effects - revealing a target's entire loadout in an instant would be more powerful than Greater Arcane Sight (which reveals just the level of their strongest spell in an instant.) That suggests it should be 8th. However, GAS is also not mind-affecting, has no save and isn't subject to SR, which makes it weaker. It also only works on one creature per casting, whereas GAS stays active for several minutes. So I would peg "Greater Spell Gauge" probably one level lower than GAS, i.e. 6th.