MemoBrain: Executive Memory as an Agentic Brain for Reasoning

Hongjin Qian, Zhao Cao, Zheng Liu


Abstract
Complex reasoning in tool-augmented agent frameworks is inherently long-horizon, causing reasoning traces and transient tool artifacts to accumulate and strain the bounded working context of large language models. Without explicit memory mechanisms, such accumulation disrupts logical continuity and undermines task alignment. This positions memory not as an auxiliary efficiency concern, but as a core component for sustaining coherent, goal-directed reasoning over long horizons.We propose MemoBrain, an executive memory model for tool-augmented agents that constructs a dependency-aware memory over reasoning steps, capturing salient intermediate states and their logical relations. Operating as a co-pilot alongside the reasoning agent, MemoBrain organizes reasoning progress without blocking execution and actively manages the working context. Specifically, it prunes invalid steps, folds completed sub-trajectories, and preserves a compact, high-salience reasoning backbone under a fixed context budget. Together, these mechanisms enable explicit cognitive control over reasoning trajectories rather than passive context accumulation.We evaluate MemoBrain on challenging long-horizon benchmarks, including GAIA, WebWalker, and BrowseComp-Plus, demonstrating consistent improvements over strong baselines.
Anthology ID:
2026.findings-acl.127
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:
2646–2662
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.127/
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Cite (ACL):
Hongjin Qian, Zhao Cao, and Zheng Liu. 2026. MemoBrain: Executive Memory as an Agentic Brain for Reasoning. In Findings of the Association for Computational Linguistics: ACL 2026, pages 2646–2662, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
MemoBrain: Executive Memory as an Agentic Brain for Reasoning (Qian et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.127.pdf
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