[HN]score: 0.35

Elasticsearch Agent Memory Layer Hits 0.89 Recall with Hybrid Search

June 18, 2026

Elastic's Agent Builder uses three indices with hybrid BM25 plus vector search, a reranker, memory supersession, and time-based decay to achieve 0.89 recall for persistent agent memory. The architecture avoids context-stuffing by storing long-term facts in Elasticsearch with document-level security, addressing the lost-in-the-middle problem. Now generally available on Elastic Cloud.

HOW THIS AFFECTS YOU

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builderYou can wire persistent cross-session agent memory into Elastic Cloud today using the documented three-index architecture with hybrid recall and decay, avoiding context window cost blowup.

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researcherThe hybrid reranker plus supersession and decay design with a concrete 0.89 recall number gives a reproducible baseline for evaluating long-term agent memory architectures.

read original ↗elastic.co

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