Channel selection · The fit · Element
The message survival
Whether what needs saying can be said here.
The part
What it is
Format constraints — length, visual dominance, sound off, skippable — determine what kind of argument is possible.
Where the message has been shortened to fit, checking whether the short version still works is the test.
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.