GUI-Primitives: Diagnosing Spatial Reasoning Failures in Vision-Language GUI Grounding

Md Abrar Jahin, Md Rizwan Parvez


Abstract
Computer-use agents ground natural-language instructions in screenshots to locate interface elements, yet existing benchmarks do not isolate whether models bind relational language to the correct element. We introduce GUI-Primitives, a 994-item benchmark of contrastive instruction pairs over seven spatial relations in graphical user interfaces (left/right, above/below, containment, alignment, proximity, list ordinal, occlusion). Each pair holds the screenshot and anchor fixed while changing the relation expression, so the correct target moves between two designated candidates. Five annotators validate a 196-item subset (𝜅 = 0.94 well-formedness; 𝜅 = 0.79 target selection). Nineteen vision-language models reach at most 32% strict point-in-box accuracy. Because models emit unconstrained coordinates, we classify each prediction by the candidate region in which it falls. Predictions fall outside both candidates on 60–92% of items. Conditional on falling within a candidate region, target selection reaches 0.82–0.90 for horizontal position, vertical position, proximity, and list ordinal, but does not differ significantly from 0.50 for containment and occlusion: most failures reflect candidate localization rather than relation understanding. Across ten models, benchmark accuracy correlates with ScreenSpot-Pro accuracy (Spearman 𝜌 = +0.74), an exploratory association at this sample size. Marking the two designated candidates raises selection accuracy by 35–57 percentage points, an oracle diagnostic that supplies the candidate set rather than a deployable method. We release the benchmark, predictions, and code.
Anthology ID:
2026.emnlp-main.2620
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:
59530–59564
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2620/
DOI:
Bibkey:
Cite (ACL):
Md Abrar Jahin and Md Rizwan Parvez. 2026. GUI-Primitives: Diagnosing Spatial Reasoning Failures in Vision-Language GUI Grounding. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 59530–59564, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
GUI-Primitives: Diagnosing Spatial Reasoning Failures in Vision-Language GUI Grounding (Jahin & Parvez, EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.2620.pdf