Tracking governance sounds like cleanup work until a team tries to compare performance across multiple brands and realizes every source label, campaign name, and funnel stage means something slightly different. Then governance becomes a growth function.
If one brand uses one source label, another brand uses a variation of the same source, and a third uses an internal nickname, the reporting layer is already compromised. That means CAC, ROAS, and funnel comparisons are all weaker than they look. Governance solves that by making the measurement layer comparable, which is exactly what makes practical attribution possible.
The first items are usually source values, medium values, campaign naming, event naming, funnel-stage definitions, and offline conversion handoff rules. Those fields create the shared language the rest of the reporting layer depends on. They should map cleanly to the stages in the customer life cycle map.
Start with the fields that directly affect reporting trust.
The rules need to be short, visible, and easy to use. A simple builder, a documented field list, and a lightweight review habit usually do more good than a giant governance manual nobody opens. The best governance layer is the one teams barely notice because it fits directly into the way they already work, while still protecting the integrity of the canonical stack.