Spellcraft check to detect caster level?

[redking]

Like it says on the can. What would be the Spellcraft DC to figure out the caster level of a spell that just got cast?

[Delta_tea]

Like it says on the can. What would be the Spellcraft DC to figure out the caster level of a spell that just got cast?

Not sure why you'd need the spell level unless you were in the act of attempting a Counter Spell. In which case you need to roll a Spellcraft check as part of the Counterspell cast. You don't get to roll and then decide to Counter Spell.

To determine level I would first ask a Spellcraft check (15 + spell level, normal), then since you want to recall Knowledge Arcana to remember what level that spell (or combination) should be. I'd set that DC low because you don't care about anything interesting, just how difficult something maybe, so probably DC5.

[Duke of Urrel]

According to everything I know about D&D, abstract attributes like "caster level" are very hard to measure. You know automatically what your OWN caster level is as a player, but you DON'T know the caster level of any enemy.

The rules do allow you to estimate the Hit Dice level of an enemy. This is done with Sense Motive skill, and the rules are discussed on page 68 of the RULES COMPENDIUM. Of course, merely estimating the Hit Dice level of an enemy as "easy," a "fair fight," a "tough challenge," or a "dire threat," is nowhere near an accurate estimate of an enemy's caster level.

More abstractly, if you know the spell level of a spell and you know the character class to which an enemy belongs, you can figure out the minimum caster level that the enemy must have. For example, if you have just identified the Polymorph spell as a fourth-level spell and you know that the enemy who cast this spell is a wizard, then you know that the minimum caster level of this enemy must be seven. (The Polymorph spell is a spell that's pretty easy to identify by its very obvious effect, which is why I chose this as an example.) In contrast, if you know that the enemy who cast the Polymorph spell is a sorcerer, you know that their minimum caster level must be eight. Knowing the spell level of a spell involves Spellcraft skill. Recognizing the character class of an enemy might involve another kind of Knowledge skill, following the judgement of your dungeon master.

On the one hand, according to the Rules as Written, it's very hard to measure the challenge that an enemy represents in D&D. On the other hand, a good dungeon master should carefully design encounters so that most of them are just difficult enough to be fun for PC parties but not likely to overwhelm them.

If your dungeon master enjoys allowing you, the PCs, frequently to encounter enemies who are overwhelmingly strong, then I would argue that it should be easier for you, the PCs, to estimate how strong your enemies are, so that you can flee when you have to. In this case, I think Delta_tea has made a decent proposal. If your survival depends on estimating how strong your enemies are, then you should be able to do that without too much difficulty.

[Biggus]

As far as I know, the only official way to do that is using the spell Spellcaster's Bane (Complete Mage p.117) which automatically tells you the caster level, but only if you have 15 ranks in Spellcraft.

If you wanted to set a DC to do it without SB, I'd base it on the fact that you need 10 more ranks to know the caster level using that spell than you do to just recognise the spell. As the DC to identify a spell being cast is normally 15 + spell level, the DC to know the caster level should be at least 25 + spell level.

[Kelb_Panthera]

There's no way to pin it down certainly, that I'm aware of, except the spellcaster's bane effect mentioned above.

You can infer it to a fair degree of accuracy through other effects though.

The vatic gaze feat will allow you to determine the highest level of spell a target can cast and arcane sight will allow you to do so as well (different checks). Typically, a caster has a CL of approximately twice the the level of the highest level spell he can cast. This can be frustrated if the target has already used up its highest level spells for the day.

Analyze dweomer will give you the CL of any effect currently on a creature, which would include any self-buffs that would be presumably cast at the target's highest CL.

As mentioned above, a sense motive check to determine the foe's approximate HD relative to your own is possible. It's rare for a dedicated caster to have a CL that's lower than their HD unless they're a hybrid character. That is, if they're both a caster and either a skill-monkey or warrior at the same time or if they're a theurge. In any case, its typically better to overestimate than under and just assume that it's at least equal to their HD.

[Miss Disaster]

On a related note, you should check out the wiz/sorc 1st level spell, 'Arcane Sensitivity' from the Shining South book.

[Quertus]

If in an appropriate setting, Teleport Through Time back to 2e, when Arcane Sight gave you that information (sort of).

For spells with a variable range, you can calculate a *minimum* caster level by the range at which they throw the spell. If it's a spread (like Fireball), you may see the spell suddenly stop at its maximum range.

[MaxiDuRaritry]

Lords of Madness allows the use of Appraise for enslavement purposes. You can use it to figure out the CR of a creature, and if that creature is a spellcaster, you can extrapolate what its inherent maximum caster level should be. (Multiclassing and RHD would reduce it, hence "maximum caster level.")