Add a Freshness Gate Before Your RAG Model Call

Retrieval systems usually rank documents by relevance. Production knowledge workflows need another question:
Is this source still valid for the task?
A highly relevant document may be archived, superseded, or too old for a time-sensitive answer. Sending it directly to a model can produce a fluent response built on expired context.
Put freshness between retrieval and generation
User query
↓
Retriever
↓
Metadata enrichment
↓
Freshness and status gate
↓
Coverage check
↓
Model endpoint
The application should send an explicit status when the available context fails the gate. That behavior is easier to review than silently generating from questionable material.
Teams evaluating model execution options for this pattern can place VectorEngine after the application-owned freshness gate.
Disclosure: this article includes an external referral link for readers who want to explore the platform.
TypeScript-style pseudocode
type RetrievedDocument = {
id: string;
text: string;
updatedAt: string;
status: "active" | "archived" | "superseded";
};

type FreshnessPolicy = {
maximumAgeMs: number;
minimumFreshDocuments: number;
};

function evaluateContext(
documents: RetrievedDocument[],
policy: FreshnessPolicy,
now = Date.now()
) {
const fresh = documents.filter((document) => {
const age = now - Date.parse(document.updatedAt);

return (
  document.status === "active" &&
  Number.isFinite(age) &&
  age >= 0 &&
  age <= policy.maximumAgeMs
);

});

return {
fresh,
rejectedIds: documents
.filter((document) => !fresh.includes(document))
.map((document) => document.id),
canGenerate: fresh.length >= policy.minimumFreshDocuments
};
}
The age window should come from the business workflow. A fixed value copied across every task is unlikely to reflect the actual risk.
Also distinguish updatedAt from ingestion time. Re-indexing an old document today does not make its underlying information current.
Freshness gates cannot establish truth. They provide a controlled way to prevent known stale or withdrawn material from being treated as ordinary context.