The guardrails

What must not get worse.

The part

What it is

A change that improves conversion and increases support contacts has not improved anything. Naming the guardrails prevents a local win being shipped as a general one.

Two or three is enough and they should be watched rather than optimised.

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.