Sorcerer's robe and strange bloodline powers

[Thereus, Silver Crusader]

There seems to be five major sorc bloodline power types:

1. Damage such as ray (including heavenly fire, which can be used 2 for good or ill) or others like minute meteors
2. Melee touch attack (with some effect such as shaken or laughing)
3. Beneficial touch
4 Physical change to sorcerer, such as claws or bite, or tanglevine
5. Item affecting such as arcane bond or imbuing weapons with shock

When using a

sorcerer's robe:

This dapper robe enables a sorcerer to add the effects of her 1st-level bloodline power to spells she casts. As a swift action before casting a spell, the wearer expends one use of her 1st-level bloodline power and selects one target of the spell to be affected by that bloodline power. If the spell allows a saving throw, a successful save against the spell means the bloodline power deals half damage (if it normally deals hit point damage) or is negated (if it does not). The robe can be used up to three times per day.

it seems straightforward on how to rule for cases 1-3 above (the target is affected by the damage or benefits, subject to applicable saving throws), but what about the case of growing claws, bite or arcane bond. What would RAW say?

[Jiggy]

Well, for starters, it says you have to expend one use, so it won't function with powers that don't have uses to spend. Which tricky cases are left?

[Leathert]

Well, Abyssal and Draconic Bloodlines have Claws for "a number of rounds per day equal to 3 + your Charisma modifier. These rounds do not need to be consecutive."

For a simple example of Type 4.

[Thereus, Silver Crusader]

Jiggy wrote:

Well, for starters, it says you have to expend one use, so it won't function with powers that don't have uses to spend. Which tricky cases are left?

Well that would take care of arcane bond I suppose. Now does "use" apply to rounds of effect?

Specifically, the player in question wants to use it for his serpentine bloodline, which normally gives him a natural bite attack plus poison (3 + CHA bonus rounds per day). We are having trouble figuring out if that means he casts a spell and:

a) He gets the bite and poison as normal for up to x rounds
b) The target of the spell (presumably an ally) gets the bite and poison attack ability for up to x rounds
c) The target (presumably hostile) get magically assaulted (from distance) by a "bite and poison" attack for up to x rounds

[Leathert]

Actually anything that usually buffs the sorcerer herself is a bit interesting/complicated with this item.

[Belafon]

I would simply say you can't use the robe with that ability. It's clearly intended to be used with abilities that can be used x times per day, not things that "can be used for x rounds per day.

(You have a fixed number of uses for the "times per day" case, where as you number of daily uses of the "rounds" case can be as little as 1 or as many as 3+CHA, depending on how you use it.)

Spoiler:

If I did allow it the answer would be that the target grows the fangs for one round. They don't have the ability to spend a free action to maintain it (or grow them again, the serpent ability is unclear on exactly what happens each round) so it's done after one. It would be different if you had (or got) to choose how many rounds they lasted when you first grew them.

Flagged for movement to the rules forum, where everyone will disagree with me :)

[Jiggy]

Leathert wrote:

Well, Abyssal and Draconic Bloodlines have Claws for "a number of rounds per day equal to 3 + your Charisma modifier. These rounds do not need to be consecutive."

For a simple example of Type 4.

That's a duration, not a number of uses. How long does "one use" last? It's undefined, because that power is limited by duration rather than number of uses. Therefore, you don't have a "use" to spend when using the robe.

[Swashbuckles]

What about the Stormborn Bloodline's "Thunderstaff" ability, as hinted above?

" At 1st level, you can touch a weapon as a standard action, giving it the shock property for a number of rounds equal to 1/2 your sorcerer level (minimum 1)."

Would this limit the robe's usefulness to spells that affect items, such as magic weapon?