That's another thing about Bloodborne where Dark Souls trumps it...
Magic and Miracles in Dark Souls are clearly labeled, there's no ambiguity about what they are...
The hunters tools, which are ostensibly "magic", and dumped at the bottom of the items list and not well explained at all...
Let's take the Augur of Ebrietas:
"Remnant of the eldritch Truth encountered at Byrgenwerth.
Use phantasms, the invertebrates known to be augurs of the Great Ones to partially summon Ebrietas."
Me after finding Augur of Ebrietas:
Partially summon?
Hmmmm, I guess that means I need to find more of these so I can fully summon Ebrietas and kill it! I'll just hang onto this for later...
Which as it turns out is not what it's for at all...
Sigh. Thanks Bloodborne... Thanks for not making a section of the interface called "Hunter Tools that can be use kind of like Magic"
That's on you, though. The game also lists it as Unlimited Use, tells you it scales "S" with Arcane, requires 18 arcane to use and 1 QS Bullet.
There's no mistaking it, this is not a consumable, you don't need to worry about losing it before getting more, even with your interpretation of the description.
This information shows up along with the description, so not even an extra square press required.
I mean, I guess it could be even more clear, but the game made it clear enough, in my opinion.
The moment you see Unlimited Use, you could just test it for yourself and you'd instantly understand what "partially summon" means.
You also only get it in the Lecture Building. Even if you get there as early as possible, through the Tonsil Stone, you still had other Hunter Tools you could have used before to know how they work, like the Old Hunter Bone, Tiny Tonitrus and Beast Roar.
EDIT: Beaten.