COLLABMEM: A Diagnostic Benchmark for Collaborative Memory Operations in Multi-Agent LLM Systems

Shun Wu, Di Wu, XueYou Zhang, Kang Liu


Abstract
Multi-agent LLM systems increasingly rely on persistent memory to coordinate role-specialized work. Correctness requires more than recalling a fact: the fact must reach the right role, remain hidden from unauthorized roles, carry the right source, and update when a more authoritative value appears. We introduce COLLABMEM, a diagnostic benchmark for collaborative memory operations. Its matched memory-only harness fixes the trace, target role, answerer, judge, and gold event, localizing errors to sharing, access, routing, provenance, conflict resolution, or retention. COLLABMEM contains 58 hand-authored scenarios (1,118 core probes), a 174-scenario scaled split (3,359 probes), adversarial and compositional hard sets, and six transactive-memory competencies. We also propose TMS-GRAPH++, a scope-aware graph memory framework with role-filtered views, writer/provenance structure, and temporal [CURRENT] marking. Across five evaluation splits, TMS-GRAPH++ achieves the highest non-Oracle average score (69.6%). Evaluations using the official SDKs of Mem0, Letta, and A-Mem show that shared archives help, but reliable collaborative memory still requires explicit visibility, provenance, authority, and retention policies. We will release the dataset, evaluation code, and reproduced outputs to support future work on multi-agent memory systems.
Anthology ID:
2026.emnlp-main.1194
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
27343–27356
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1194/
DOI:
Bibkey:
Cite (ACL):
Shun Wu, Di Wu, XueYou Zhang, and Kang Liu. 2026. COLLABMEM: A Diagnostic Benchmark for Collaborative Memory Operations in Multi-Agent LLM Systems. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 27343–27356, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
COLLABMEM: A Diagnostic Benchmark for Collaborative Memory Operations in Multi-Agent LLM Systems (Wu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1194.pdf