What the member's desks did on the LAST COMPLETED ET SESSION.

The "Yesterday" line on /alphas. Facts with units and nothing else: how many fills, across how many bots, and the last one. No projection, no "doing well", no comparison to anything.

THE DAY IS THE EXCHANGE CALENDAR, never date.today() - 1 (market_calendar.prev_session, which knows the holidays and the half-days). On a Monday "yesterday" is FRIDAY, and on the day after Thanksgiving it is Wednesday — a calendar day would report an honest zero about a day the market never opened, and a zero is exactly what a broken walk looks like. The session we measured is returned WITH the numbers so the reader can see which day they describe.

READ-ONLY, session-scoped: a member sees their OWN desks and no others. A member with no desk gets zeros and a null last — that is a fact about an empty book, not an error.