From Recall to Forgetting: Benchmarking Long-Term Memory for Personalized Agents

Md Nayem Uddin, Kumar Shubham, Eduardo Blanco, Chitta Baral, Gengyu Wang


Abstract
Personalized agents that interact with users over long periods must maintain persistent memory across sessions and update it as circumstances change. However, existing benchmarks predominantly frame long-term memory evaluation as fact retrieval from past conversations, providing limited insight into agents’ ability to consolidate memory over time or handle frequent knowledge updates.We introduce Memora, a long-term memory benchmark spanning weeks to months long user conversations. The benchmark evaluates three memory-grounded tasks: remembering, reasoning, and recommending. To ensure data quality, we employ automated memory-grounding checks and human evaluation. We further introduce Forgetting-Aware Memory Accuracy (FAMA), a metric that penalizes reliance on obsolete or invalidated memory when evaluating long-term memory. Evaluations of four LLMs and six memory agents reveal frequent reuse of invalid memories and failures to reconcile evolving memories. Memory agents offer marginal improvements, exposing shortcomings in long-term memory for personalized agents.
Anthology ID:
2026.findings-acl.1337
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
26814–26841
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1337/
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Cite (ACL):
Md Nayem Uddin, Kumar Shubham, Eduardo Blanco, Chitta Baral, and Gengyu Wang. 2026. From Recall to Forgetting: Benchmarking Long-Term Memory for Personalized Agents. In Findings of the Association for Computational Linguistics: ACL 2026, pages 26814–26841, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
From Recall to Forgetting: Benchmarking Long-Term Memory for Personalized Agents (Uddin et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1337.pdf
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