It's hard not to use it when it's the one from the case law.

> That's not quite the same thing as curating a set of recipes into a cookbook and thereby exercising creativity in the "selection, coordination, and arrangement" of those recipes.

Exercising creativity can't be the hook if recipes have that and aren't copyrightable. You exercise creativity in choosing whether to specify chocolate chips or peanut butter chips or licorice bits etc.

APIs have hierarchy, but recipes have that too. You make butter from milk. You make cookies from butter. You make cookie crumb topping from cookies.

It's all already there in a recipe without reaching the result you want. You choose chocolate chips over peanut butter chips. You combine them with cookie ingredients to make cookies and brownie ingredients to make brownies. Selection, coordination, and arrangement. But the end result is still just a list of facts about how to make those cookies/brownies.

So why look at those things sometimes but not others? Because sometimes it applies to a work of authorship, but sometimes it applies to function, and you can't copyright function. So the functional part shouldn't count.

And that's what an API is. It's a formal functional specification. It's a list of facts about how to call those function implementations. It's the exact piece you don't get credit for.

Anything required for interoperability, is functional.