The Ghast Stiletto is an interesting example.
Generally I would run it that an item that you are wielding that casts an emanation, you can still choose to exclude yourself from the area as long as you are at the center of it. You couldn't choose to exclude a different creature or other potential target even if they were in the same space as you, and you couldn't exclude yourself if you are in the area and no longer at its center - as is normal for emanations.
This doesn't come up with things like a Wand of Bless because the wand is just providing power for the spell. The caster is still casting the spell.
But if there was a brooch or something that had an envision activation that casts 3-action Heal, I would still let the caster choose to exclude themselves if desired.
Now for the Ghast Stiletto: from the RAI line it is pretty clear that the emanation is coming from the target creature, not the wielder of the item. The target creature is also always affected since it explicitly states that. So yes, the wielder of the Ghast Stiletto is going to be subjected to the stench and resulting save and effect once they use the item's ability.
I see this being useful for a hit-and run type of character. Something like a spellcaster that wants to have something nasty to use on an enemy that closes in for melee attacks. Enemy comes in and hits them, instead of immediately running away on their turn, they hit them with the Stiletto and then run.
From the Official Pathfinder FAQ and Errata documentation:
So the general rule of thumb is that most emanations do NOT impact you unless you wish it. There are exceptions (such as antimagic field or storm lord), but they are explicitly called out.
Except for cursed items and some artifacts, magical items in PF2e are not "use at your own risk." They almost always benefit those using them (or at the very least do not hinder them).
From the Official Pathfinder FAQ and Errata documentation:
Right. Which is why a Wand of Harm isn't going to risk damaging the caster - because when using a wand, it is still the caster that is creating the effect.
But what about an item that is creating the emanation itself instead of granting the power to a creature that is wielding it? Even if the item can choose to not include itself in the emanation area, that would mean that the creature holding the item is still affected.
Which, to me, doesn't make a lot of sense from a game balance standpoint. I don't think that is the intended ruling. But it is very arguably RAW.
If the item in question needs to be activated by an individual, and doesn't say anything about the activator being effected, then I think it's safe to say that you follow the normal rules: the activating individual gets to choose whether or not they are effected by the emanation.
However, if the item is activated via some other external trigger, such as a trap being sprung, then all bets are off.
RAI might be different, but RAW is as breithauptclan describes.
Where RAW conflicts with known RAI it is generally better to ignore it.
RAI might be different, but RAW is as breithauptclan describes.Where RAW conflicts with known RAI it is generally better to ignore it.
The problem is that not everyone agrees that it is the RAI for the wielder of the weapon to not be affected.
The Ghast Stiletto is pretty clear that the creature at the center of the emanation - the one that could possibly be excluded from being affected - is the target of the attack, not the wielder of the dagger. Just as clear is that the target of the attack is not going to be excluded from the effect.
For other items that are creating effects, the RAW is a bit strange and I would go with RAI that items that you wield that are creating emanations centered on the item can exclude the wielder of the item from the area if desired.
Also for the Ghast Stiletto, I am going with the RAI that the stench effect has the Aura trait and follows the target around rather than being a fixed position centered where the attack happened.