A protocol artist, in my very narrow definition, is one that builds the creative endeavor on the design of a protocol, the design of a system.
Primavera De Filippi, Strange Rules: Protocol Art at the Venice Biennale
Meaning, if I'm a typographer, if I'm a graphic designer and I'm making a poster and I pick a typography or a font, the font that I choose has a history. There's someone who created it for a certain purpose, and it's used in a certain way.
Dejha Ti, Protocol Art & Blockchain Formalism