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When Retrieval Is Not Enough: Obsolete Facts in Agent Memory
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First announced by arXiv: 2026-10-28 · Indexed by Pub-AI: 2026-10-28 UTC
When Retrieval Is Not Enough: Obsolete Facts in Agent Memory
First announced by arXiv: 2026-10-28 · Original record ↗
- arxiv
- 2610.36308
Explicit source versions (1)
- v1 · Date not supplied
- Preprint available
Source date: 2026-10-28 · First detected: 2026-10-28 UTC · Historical baseline
Source evidence (1)
- Official evidence ↗ · RSS guid=oai:arXiv.org:2610.36308v1; arxiv:announce_type=new; item pubDate (official metadata)
Abstract · arxiv
Memory-agent benchmarks often collapse retrieval and answer generation into one score, making it hard to tell whether a failure comes from missing an update or from not using an update that was already retrieved. We examine this distinction on the single-hop FactConsolidation task of MemoryAgentBench. With Qwen2.5-7B-Instruct on 6K-history BM25 accuracy drops from 45% to 32% when the retrieved evidence budget grows from 64 to 512 tokens, even though a gold-assisted post-hoc audit finds the newest statement in every retrieved set. Most of the errors occur on questions that also contain an obsolete statement version. Under a frozen prompt and equal four-statement evidence size, replacing one unrelated statement with the obsolete competing statement reduces accuracy from 100% to 44.6% for Qwen2.5 and from 100% to 87.8% for Qwen3-14B, with all 50 harmful paired flips classified as stale. A 32K-history replication likewise favors BM25-64 over BM25-512 (69% versus 58%). These results suggest that retrieving the correct fact is not enough. An obsolete competing statement can be more harmful than an unrelated piece of evidence of the same size.