Thanks for making this PEP Josh, I think it could be quite useful. One thing I'd like to see, as someone who hasn't actually needed this feature myself but can imagine use cases, is a few examples in the Motivation section illustrating some contexts where this would help. Something I'd suggest calling out is why a classmethod / staticmethod won't suffice. I tend to use that in my code when I need conversions, e.g. ``` @dataclasses.dataclass class Dataclass: x: TypeDerivedFromString @staticmethod def create(x: str): return Dataclass(x=DerivedFromString(x)) ``` I'm *guessing* that the motivation for not needing a creator method to do conversions is some combination of: - wanting to reduce verbosity - at least to me this argument may not land well, given a preference for explicit over implicit logic - wanting to be able to modify automated type-derived logic like serialization - my guess is that use cases like this will be very compelling Cheers, Steven Troxler