The constraints

What is fixed and what is open to negotiation.

The part

What it is

Being explicit about what cannot move is a courtesy that saves a round of proposals. Budget, deadline and scope are rarely all fixed, and saying which is not is the useful part.

Where everything is stated as fixed, the catchball step is theatre.

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.