Continuity of state · The carried context · Element
The depth
How far back the history reaches.
The part
What it is
The current episode, the last few interactions, or everything. Each level costs more and adds less than the one before it.
The last three interactions covers the great majority of situations where history matters.
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.