The metric

The unit that is charged for, defined precisely enough that both sides count it the same way.

The part

What it is

Ambiguity in the definition surfaces at invoicing. What counts as an active user, or as a transaction, needs settling before anything is billed.

A metric that only you can measure is not a metric a customer will trust for long.

The smallest level

The attributes it carries

Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.

Metric
The unit itself, defined in terms both parties can verify.
Text shared type
Metric family
Per seat, per usage, per outcome, flat or hybrid — each shapes behaviour differently.
Choice shared type
Counting rule
How it is counted, which is where invoicing disputes actually originate.
Text shared type