SkillMol: Skill-Conditioned Action Editing for Molecular Optimization

Jiajun Yu, Kun Li, Zhihao Wu, Weifan Mao, Yizhen Zheng, Haishuai Wang


Abstract
Existing LLM-based molecular optimization methods frame the task as molecule-to-molecule mapping, forcing models to implicitly learn structure-property relationships from paired SMILES alone. We argue this misses a key ingredient: task-level chemical knowledge that tells the model which structural motifs to prefer or avoid for a given property direction, before it ever looks at a specific molecule. We propose SkillMol, which constructs compact task skills – sets of recommended and discouraged structural motifs for each optimization objective – from domain knowledge, and pairs them with an atom-anchored action interface that decomposes editing into discrete, executable operations. Skills are used twice: as explicit training context so the model learns skill-conditioned edit actions, and as functional-group constraints during inference search. A deterministic RDKit executor applies the proposed graph edits. On the MoleculeSTM benchmark across 14 molecular editing tasks, SkillMol achieves 92.5% loose and 80.0% strict hit ratio on single-property tasks and 65.3% average across loose and strict multi-property columns, outperforming strong LLM baselines. Our code can be found at https://github.com/jiajunyu1999/SkillMol.
Anthology ID:
2026.findings-emnlp.920
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
Note:
Pages:
19428–19445
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.920/
DOI:
Bibkey:
Cite (ACL):
Jiajun Yu, Kun Li, Zhihao Wu, Weifan Mao, Yizhen Zheng, and Haishuai Wang. 2026. SkillMol: Skill-Conditioned Action Editing for Molecular Optimization. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 19428–19445, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SkillMol: Skill-Conditioned Action Editing for Molecular Optimization (Yu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.920.pdf