Free action + Spell like ability

[yonman17]

I can’t find info if casting a free action spell like ability provokes an attack of opportunity.
Example:
Black Blade Strike (Sp): As a free action, the magus can spend a point from the black blade’s arcane pool to grant the black blade a +1 bonus on damage rolls for 1 minute. For every four levels beyond 1st, this ability gives the black blade another +1 on damage rolls.

[Toshy]

While I can't find a direct rule, I would say no. Reasoning as follows:

Spell-Like Abilities wrote:

Spell-like abilities are magical and work just like spells.

Using all other spell-like abilities is a standard action unless noted otherwise, and doing so provokes attacks of opportunity.

As noted in Black Blade Strike, it is not a standard action, but a free one. An SP works like a spell, so what does the descriptions of spells say about free action casting and provoking?

Casting a Spell wrote:

Generally, if you cast a spell, you provoke attacks of opportunity from threatening enemies.

Spells that require only a swift action to cast don’t provoke attacks of opportunity.

Okay so a swift action cast, doesn't provoke an AoO, but nothing about free action castings.

Free Action wrote:

Free actions don’t take any time at all, though there may be limits to the number of free actions you can perform in a turn. Free actions rarely incur attacks of opportunity.

So, free actions take even less time than swift actions and swift action castings already don't provoke.

Even more, it's also mentioned that free actions rarely incur AoOs.

In conclusion I would rule, that it doesn't provoke an AoO.

But I might be corrected, as the description of spell-like abilities I quoted in the beginning, could also be read that all spell-like abilities provoke AoOs, regardless of their "casting time".

[OmniMage]

What class? I'm guessing Bladebound Magus (its one of the search results on AoN).

[Azothath]

I don't see explicit RAW, but a Free is considered less effort than a Swift (see descriptions).
Combat rules you can scroll down to Free Action (can be taken during another action), Table 7-2: Actions in Combat, Cast a Spell - Attack of Opportunity: (... Spells that require only a swift action to cast don’t provoke attacks of opportunity.), Use Special Ability - Spell-like Abilities(Sp): Using a spell-like ability works like casting a spell in that ... standard action, unless the ability description notes otherwise.

That should do it. Otherwise the description would have to note that it provokes an AoO.

"Free actions rarely incur..."

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the OP is referring to Magus arch Bladebound, Black Blade Ability descriptions - Black Blade Strike (Sp): As a free...

[Diego Rossi]

Quote:

Black Blade Strike (Sp): As a free action, the magus can spend a point from the black blade’s arcane pool to grant the black blade a +1 bonus on damage rolls for 1 minute. For every four levels beyond 1st, this ability gives the black blade another +1 on damage rolls.

For this specific ability, I think (Sp) is an error, it should be (Su).

As a general rule, I agree with the others, it should not provoke. Swift/Immediate spells don't provoke and a free spell requires even less time and effort.

Another example of a free action casting:

Spell Storing weapon ability wrote:

Anytime the weapon strikes a creature and the creature takes damage from it, the weapon can immediately cast the spell on that creature as a free action if the wielder desires. (This special ability is an exception to the general rule that casting a spell from an item takes at least as long as casting that spell normally.)

I have never heard of someone arguing that the weapon would provoke when casting the spell.