DYNAMO: Dynamic Skill-Tool Evolution for Vision-Language Agents

Yutao Sun, Yanting Miao, Hao-Xuan Ma, Mengyu Zhou, Mingshuai Chen, Tiancheng Zhao, Dexin Wang, Lei Lv, Li Xu, Xiaoxi Jiang, Guanjun Jiang


Abstract
Improving vision-language models (VLMs) on visual reasoning typically requires retraining or hand-designed prompts and tools. We present Dynamo, a training-free framework that adapts a frozen VLM without any weight updates. On a small labeled training subset, the agent inspects its own correct and incorrect attempts and evolves two complementary capabilities: reusable reasoning skills for cognitive bottlenecks, and executable visual tools for perceptual ones. Each generated tool is paired with a skill that specifies when to invoke it, and both capability types accumulate in a persistent library. Across four visual reasoning benchmarks and five VLM backbones, Dynamo improves direct inference on all 20 model–benchmark settings (avg. +5.6 acc). When the tool set is given in advance, the framework learns when to call each tool, and per-step tool choice improves on every tested backbone. Against task-specific RL (VTool-R1, DeepEyes), Dynamo closes 65–99% of the RL gap at a fraction of the compute, and combines additively with RL when available.
Anthology ID:
2026.emnlp-main.774
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:
17994–18015
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URL:
https://aclanthology.org/2026.emnlp-main.774/
DOI:
Bibkey:
Cite (ACL):
Yutao Sun, Yanting Miao, Hao-Xuan Ma, Mengyu Zhou, Mingshuai Chen, Tiancheng Zhao, Dexin Wang, Lei Lv, Li Xu, Xiaoxi Jiang, and Guanjun Jiang. 2026. DYNAMO: Dynamic Skill-Tool Evolution for Vision-Language Agents. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 17994–18015, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
DYNAMO: Dynamic Skill-Tool Evolution for Vision-Language Agents (Sun et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.774.pdf