SkillHone: A Harness for Continual Agent Skill Evolution Through Persistent Decision History

Zhiwei Li, Yong Hu


Abstract
Agent skills extend language-model agents with task-specific procedures, scripts, and references, but the tasks and environments they target continually change. Existing methods improve skills in bounded runs and retain only the final artifact, discarding the decision history that later agents need to interpret prior revisions, evaluations, and rejected alternatives. We introduce SkillHone, a harness for continual agent skill evolution grounded in persistent decision history. SkillHone pairs skill revisions with evaluation-side evidence that supplies practice feedback, recording structured histories of diagnoses, revisions, evidence, and outcomes. Role-separated subagents run candidate skills on practice probes with redacted reporting and propose revisions informed by prior decisions, enabling cross-session refinement without rediscovering past rationale. On deep-research benchmarks, SkillHone runs without a pre-integrated search stack and outperforms the commercially backed deep-research agent by 15.8 points on GAIA and 3.2 points on WebWalkerQA-EN, while also exceeding prior skill-evolution methods. We further deploy SkillHone on internal tool-mediated analysis scenarios, where it improves accuracy by an average of 18.8 points across seven settings.
Anthology ID:
2026.emnlp-industry.105
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
1819–1829
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.105/
DOI:
Bibkey:
Cite (ACL):
Zhiwei Li and Yong Hu. 2026. SkillHone: A Harness for Continual Agent Skill Evolution Through Persistent Decision History. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 1819–1829, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SkillHone: A Harness for Continual Agent Skill Evolution Through Persistent Decision History (Li & Hu, EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.105.pdf