Delta mode for daily/recurring monitoring: returns only publications that are new, changed (a fingerprinted amendment - a new monto, document, date...) or closed since a previous run. Seen ids are persisted across runs in a named key-value store unique to this actor ("salta-compras-monitor-delta-state"), not the run's own default store (which is isolated per run and would not survive between scheduled runs). Every record still carries is_new, so a normal (onlyNew=false) run also tells you which of its results are new. Pagination is NOT stopped early once already-seen records are reached: this actor's listing is sorted by Fecha/Hora Apertura (the bid-opening deadline), not by when a publication was created, so a genuinely new publication can appear on any page - onlyNew filters after a full fetch up to maxItems instead of short-circuiting it. See AGENTS.md for the live evidence behind this.