Delta mode for recurring/scheduled monitoring: returns only tenders that are new, changed to a different estado_compra (a real lifecycle transition, e.g. upcoming -> awarded) or amended (a changed monto, renglon or date) since a previous run. Tracked cross-estado, per idCompra, in this actor's own named key-value store (tucuman-compras-monitor-delta-state), so it survives between scheduled runs - unlike the run's default key-value store, which is created fresh per run. Implemented as a POST-FILTER: this actor still fetches up to maxItems as usual and only then drops unchanged already-seen ids, rather than stopping pagination early once N pages come back with nothing new. Early-stop is NOT used here because this portal's own listing order was verified live (2026-09-06) to be sorted by each tender's own opening-date field - ascending for estado 1, descending for estado 3 - not by when the tender was added to the site, so a later page can hold a genuinely new tender while an earlier page is full of ones already seen. See AGENTS.md for the page-by-page evidence.