Promise, pillars, proof — the talk track, not the brand book.
A messaging framework is the operating document for language: audience, one promise, benefit pillars, proof, objections, and examples. Sales, site, and ads should be able to lift from it without inventing a second story.
Not brand guidelines (voice and visual). Not a positioning statement (the frame). Not a slogan list. If it does not have proof under each pillar, it is a mood board.
One page for the map, a few pages for examples and objections. A 40-page PDF will not get opened.