Fitting with the image or brand of someone or something. This phrase can refer to a company brand or (perhaps humorously) to someone's personal interests or image. Their newest commercial is so on brand that you can tell it's for their product before you even see it. That book on the lunar phases is very on brand for you, what with your interest in astronomy.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.