@inproceedings{bian-etal-2026-membook,
title = "{M}em{B}ook: A Hierarchical Reasoning-based Memory Framework for Hallucination-Resistant {LLM} Agents",
author = "Bian, Tongshu and
li, Yunxin and
Xu, Zhenran and
Shi, Tianqi and
Wang, Longyue and
Hu, Baotian and
Zhang, Min",
editor = "Lee, Hung-Yi and
Dev, Sunipa and
Li, Jessy and
Elliott, Desmond",
booktitle = "Findings of the {A}ssociation for {C}omputational {L}inguistics: {EMNLP} 2026",
month = oct,
year = "2026",
address = "Budapest, Hungary",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.findings-emnlp.1847/",
pages = "39444--39470",
ISBN = "979-8-89176-462-0",
abstract = "Memory is a cornerstone of foundation model-based agents for ultra-long-term interaction. However, hallucinated or noisy information can accumulate inside memory systems and progressively contaminate downstream tasks. Existing systems face two key challenges: (1) memory construction mechanisms trade off between faithful recall and hallucination suppression; and (2) retrieval relies on shallow semantic similarity, failing to distinguish logically irrelevant memories. We propose **MemBook**, a hierarchical time-aware memory framework for hallucination-resistant agents. For memory construction, MemBook introduces a stateful memory stabilization mechanism that prevents hallucinated claims from being consolidated into persistent memory and organizes reliable memories into an evolving Session{--}Chapter{--}Memory Point hierarchy. For memory retrieval, MemBook performs reasoning-based hierarchical retrieval over this evolving memory book to identify temporally and logically relevant memories. Experiments on HaluMem-Medium, HaluMem-Long, and LongMemEval show that MemBook improves extraction quality and downstream performance while suppressing cross-stage hallucination propagation. Notably, MemBook remains stable under ultra-long contexts, outperforming GAM by absolute 19.57{\%} QA accuracy improvement on HaluMem-Long."
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<abstract>Memory is a cornerstone of foundation model-based agents for ultra-long-term interaction. However, hallucinated or noisy information can accumulate inside memory systems and progressively contaminate downstream tasks. Existing systems face two key challenges: (1) memory construction mechanisms trade off between faithful recall and hallucination suppression; and (2) retrieval relies on shallow semantic similarity, failing to distinguish logically irrelevant memories. We propose **MemBook**, a hierarchical time-aware memory framework for hallucination-resistant agents. For memory construction, MemBook introduces a stateful memory stabilization mechanism that prevents hallucinated claims from being consolidated into persistent memory and organizes reliable memories into an evolving Session–Chapter–Memory Point hierarchy. For memory retrieval, MemBook performs reasoning-based hierarchical retrieval over this evolving memory book to identify temporally and logically relevant memories. Experiments on HaluMem-Medium, HaluMem-Long, and LongMemEval show that MemBook improves extraction quality and downstream performance while suppressing cross-stage hallucination propagation. Notably, MemBook remains stable under ultra-long contexts, outperforming GAM by absolute 19.57% QA accuracy improvement on HaluMem-Long.</abstract>
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%0 Conference Proceedings
%T MemBook: A Hierarchical Reasoning-based Memory Framework for Hallucination-Resistant LLM Agents
%A Bian, Tongshu
%A li, Yunxin
%A Xu, Zhenran
%A Shi, Tianqi
%A Wang, Longyue
%A Hu, Baotian
%A Zhang, Min
%Y Lee, Hung-Yi
%Y Dev, Sunipa
%Y Li, Jessy
%Y Elliott, Desmond
%S Findings of the Association for Computational Linguistics: EMNLP 2026
%D 2026
%8 October
%I Association for Computational Linguistics
%C Budapest, Hungary
%@ 979-8-89176-462-0
%F bian-etal-2026-membook
%X Memory is a cornerstone of foundation model-based agents for ultra-long-term interaction. However, hallucinated or noisy information can accumulate inside memory systems and progressively contaminate downstream tasks. Existing systems face two key challenges: (1) memory construction mechanisms trade off between faithful recall and hallucination suppression; and (2) retrieval relies on shallow semantic similarity, failing to distinguish logically irrelevant memories. We propose **MemBook**, a hierarchical time-aware memory framework for hallucination-resistant agents. For memory construction, MemBook introduces a stateful memory stabilization mechanism that prevents hallucinated claims from being consolidated into persistent memory and organizes reliable memories into an evolving Session–Chapter–Memory Point hierarchy. For memory retrieval, MemBook performs reasoning-based hierarchical retrieval over this evolving memory book to identify temporally and logically relevant memories. Experiments on HaluMem-Medium, HaluMem-Long, and LongMemEval show that MemBook improves extraction quality and downstream performance while suppressing cross-stage hallucination propagation. Notably, MemBook remains stable under ultra-long contexts, outperforming GAM by absolute 19.57% QA accuracy improvement on HaluMem-Long.
%U https://aclanthology.org/2026.findings-emnlp.1847/
%P 39444-39470
Markdown (Informal)
[MemBook: A Hierarchical Reasoning-based Memory Framework for Hallucination-Resistant LLM Agents](https://aclanthology.org/2026.findings-emnlp.1847/) (Bian et al., Findings 2026)
ACL