Updating that `Provider` type definition seems like it would be the simplest part of implementing/adding a new authentication provider, so I don't understand why you would ever want to avoid updating it and in doing-so completely short-cut the existing type safety. But also what people want to do in the privacy of their own code-base is none of my business.

I also don't understand what you mean by `Typesafety for "google" and "github", but any other string is also welcome.` That's no type safety at all, is it? "goggle" and "gittub" and "" and "bacefook" are all valid with this "hidden typescript hack you need to know".