Calibrating metadata filter gates in news monitoring retrieval

A technical guide argues that metadata filters should be applied both before and after semantic retrieval, with each gate measured separately. The approach separates what is semantically relevant from what a subscriber is permitted to see, such as region, language, publication window, or source list. It recommends storing explicit metadata fields with a small schema contract and checking recall, p95 latency, and removed candidates against a reviewed set of 2,000 alert queries. The article includes typed code for filter definitions and request validation, including candidate limit bounds and date range checks. It describes three gates: temporal and contractual filtering, tenant and geography policy, and semantic safety through deduplication.