Identity
Guidelines versus decision rules
Why only one of them ever gets followed after the launch deck.
The difference
A guideline describes an outcome. A decision rule describes how to choose. “Our tone is confident but warm” is a guideline; nobody has ever been unblocked by it. “When the two conflict, choose clarity over warmth” is a rule, because it resolves a specific argument at a specific moment.
Why guidelines decay
Guidelines are written for the launch and consumed by people who were in the room. Rules are written for the argument in eighteen months between two people who were not.