Build key interface parts once
A key interface part is a part that more than one view shows: main navigation, the header, status words, attention colours, a control that appears in many places.
What it can see: only this page.
The rule itself
A key interface part is a part that more than one view shows: main navigation, the header, status words, attention colours, a control that appears in many places. Build each key part once, as one component, and use that component in every view.
When a new view needs a key part that already exists, use the component. Do not copy it, and do not draw a part that only looks the same.
A part that belongs to one page goes beside or under the shared part. It never replaces the shared part.
A mock or prototype starts from the product's shared parts. It does not draw its own header or navigation.
A change to a key part changes every view at once. Before you call the change complete, look at each view that uses the part.
Use it
Copy the rule into your agent's rules folder, or add it with a kit that lists it. Your agent reads it at the start of each session.