CMAS: Enhancing Data Augmentation for Molecular Graph Classification via a Collaborative Multi-Agent System

Xuanting Fan, Chenyu Wang, Xin Liu, Weiyi Ren, Yifan Wang, Xiao Luo


Abstract
Data augmentation is widely adopted in molecular graph learning due to its practical benefits in enhancing model performance. However, conventional augmentation like edge deletion often destroys critical chemical semantics, as molecular properties are highly sensitive to structural changes. To address this, we introduce CMAS, a novel  ̲Collaborative  ̲Multi- ̲Agent  ̲System for enhancing data augmentation in molecular graph classification. Specifically, for each input molecule, we first use a BRICS-based decomposition strategy with prompt-guided LLM generation to produce structurally diverse candidates while preserving the core scaffold. To ensure that the generated candidates preserve the physicochemical properties of the original molecule, we retrieve domain-specific chemical knowledge from a knowledge graph and prompt an LLM to assess property consistency, effectively filtering out semantically divergent samples. Finally, we perform rule-based sanitization with iterative feedback to ensure chemical validity and preserve distributional diversity, resulting in a high-quality augmented molecular set. Extensive experiments on MoleculeNet benchmarks validate the superiority of CMAS against several state-of-the-art baselines. Code is available at https://github.com/Catfromuibe/CMAS.
Anthology ID:
2026.findings-emnlp.2300
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
49310–49328
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URL:
https://aclanthology.org/2026.findings-emnlp.2300/
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Cite (ACL):
Xuanting Fan, Chenyu Wang, Xin Liu, Weiyi Ren, Yifan Wang, and Xiao Luo. 2026. CMAS: Enhancing Data Augmentation for Molecular Graph Classification via a Collaborative Multi-Agent System. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 49310–49328, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CMAS: Enhancing Data Augmentation for Molecular Graph Classification via a Collaborative Multi-Agent System (Fan et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.2300.pdf