VTOS: Learning to Orchestrate Vision Tools by Co-Searching Solutions and Observers

Jinchao Ge, Lingqiao Liu, Shuwen Zhao, Lei Wang


Abstract
Vision foundation tools such as open-vocabulary detectors, segmentation models, and post-processing operators are powerful building blocks for computer vision, but their effectiveness depends heavily on how they are orchestrated: which tools are used, in what order, with what parameters, and under what visual conditions. Existing visual-programming agents typically generate a fixed solution pipeline, making them brittle under dense objects, occlusion, small targets, and domain shift. We introduce VTOS (Vision Tools Orchestration Search), a framework for adaptive visual tool orchestration through joint solution–observer search. VTOS co-searches executable solution programs that compose vision tools such as Grounding DINO, SAM, NMS, and slice-and-detect, together with observer programs that diagnose candidate solutions, identify failure modes, and generate actionable feedback. These observations are accumulated in a shared VisionThoughts knowledge base to guide subsequent search. We evaluate VTOS through two case studies: dense object counting on LVIS-Count and zero-shot plant-disease segmentation on PlantSeg-OOD, which stress different orchestration challenges including threshold calibration, NMS, slicing, mask refinement, and domain generalization. Across both tasks, VTOS outperforms static tool pipelines and agentic visual-programming baselines, specifically in complex settings such as dense, occluded scenes and out-of-distribution segmentation where static pipelines leave measurable headroom, rather than in standard tasks where a single well-calibrated tool already approaches its ceiling.
Anthology ID:
2026.emnlp-main.977
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
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Pages:
22551–22569
Language:
URL:
https://aclanthology.org/2026.emnlp-main.977/
DOI:
Bibkey:
Cite (ACL):
Jinchao Ge, Lingqiao Liu, Shuwen Zhao, and Lei Wang. 2026. VTOS: Learning to Orchestrate Vision Tools by Co-Searching Solutions and Observers. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 22551–22569, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
VTOS: Learning to Orchestrate Vision Tools by Co-Searching Solutions and Observers (Ge et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.977.pdf