A solid ring in matte silver with the phrase "someone who fits the culture" engraved on the inside, where only the wearer can see it. It is not decorative. It is diagnostic. Wear it to every kick-off. When the phrase comes up, look at the ring, remember it has never once come with a definition attached, and ask the question that turns it into a real requirement before you start the search.
Wear daily. Turn it when "culture fit" is said. Follow with "could you give me one example."
Part of The Control Room, for those who can't see what's working.