WebCompass: Evaluating Multimodal Code Agents in Web Development from Vision, Instruction, and Interaction to Implementation

Xinping Lei, Xinyu Che, Junqi Xiong, Chenchen Zhang, Yukai Huang, Chenyu Zhou, Haoyang Huang, Minghao Liu, Letian Zhu, Hongyi Ye, Ken Deng, Zizheng Zhan, Han Li, Yifan Yao, Ming Sun, Zhaoxiang Zhang, Jiaheng Liu


Abstract
Large language models are increasingly deployed as interactive coding agents for end-to-end web development, yet existing benchmarks evaluate narrow slices of this workflow—typically text-conditioned generation with static correctness metrics—overlooking visual fidelity, interactivity, and codebase-level reasoning. We introduce WebCompass, a benchmark that covers the full web development lifecycle by spanning three input modalities (text, image, video) and three task types (generation, editing, repair). To match the diverse nature of these tasks, we pair checklist-guided LLM-as-a-Judge for patch-based evaluation with a novel Agent-as-a-Judge protocol that executes generated websites in a real browser and synthesizes targeted test cases. Experiments on ten models reveal a 25-point gap between the best closed- and open-source models, persistent weaknesses in visual aesthetics even among frontier systems, and divergent performance profiles across task types that challenge the notion of a single "best" web coding agent.
Anthology ID:
2026.emnlp-main.1669
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:
37948–37984
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1669/
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Bibkey:
Cite (ACL):
Xinping Lei, Xinyu Che, Junqi Xiong, Chenchen Zhang, Yukai Huang, Chenyu Zhou, Haoyang Huang, Minghao Liu, Letian Zhu, Hongyi Ye, Ken Deng, Zizheng Zhan, Han Li, Yifan Yao, Ming Sun, Zhaoxiang Zhang, and Jiaheng Liu. 2026. WebCompass: Evaluating Multimodal Code Agents in Web Development from Vision, Instruction, and Interaction to Implementation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 37948–37984, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
WebCompass: Evaluating Multimodal Code Agents in Web Development from Vision, Instruction, and Interaction to Implementation (Lei et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.1669.pdf