The interest poll Shipped
Discretionary specialists are each asked whether this change is in their area, seeing only their own description and the changeset — never the roster.
Every remaining discretionary specialist is polled individually. It sees its own description and the changeset, and nothing else — not the roster, not the other candidates' answers. There is no central overseer deciding who reviews, because an overseer is a single model whose blind spot silently becomes the whole run's blind spot.
Why bottom-up costs less than it sounds
The poll is a small, cheap dispatch per candidate, and it exists to avoid a much larger one — handing a full diff to a specialist that has nothing to say about it. The floor guarantees coverage, the poll buys breadth, and neither requires a model to hold the whole roster in its head.