Compaction cannot read your priorities
A summary can preserve events and still lose priority. It may say that three options were discussed, but not that the human hated option two, temporarily tolerated option three, and silently assumed option one is now canonical. The events survive; the live ranking dies.
The human collaborator carries living intent: current priorities, social context, project risk, authority boundaries, and the emotional meaning of corrections. That intent must be made explicit before compaction or handoff, or it gets compressed away as 'discussion noise.'
Steering beats reminding
Repeating 'remember this' is weak. Steering says what changed: this rule is now canonical, that document is outdated, this action needs approval, this file is owned by another session. Steering is a state transition the model can verify; reminding is a vibe.
The arbiter pattern
In a long collaboration, every decision point goes through the human as arbiter: 'option A vs B?' 'this still matters?' 'authorize the push?' This is not micromanagement; it is who-decides-what discipline. Long sessions without an arbiter drift toward the model's defaults, which were trained on average internet behavior, not your project.