MelonBench: A Benchmark for Coded Entity Resolution over Noisy Web Evidence

Zhishan Lin, Jingxiao Li, Yanbing Zhang, Ziyan Liu, Yuqing Shao, Yunfei Tong, Ganghao Liu, Qian Zhang, Zhe Wang


Abstract
Large language models (LLMs) are increasingly deployed as web-browsing agents, yet current benchmarks mostly evaluate explicit queries over clean factual evidence. We introduce Melonbench, a 665-item benchmark for coded entity resolution over noisy open-web user-generated content, instantiated with mid-to-long-tail public figures in Chinese entertainment blind-item discourse. Solving Melonbench requires agents to decode obfuscated clues, retrieve fragmented evidence, and identify the target entity. The benchmark is constructed through a five-stage semi-automatic pipeline with atomic event stratification, adversarial faithfulness auditing, and expert verification. Across 30 systems, the best non-search model reaches 25.1% accuracy and the best search-enabled system reaches 49.9%. Controlled comparisons of the same models with and without web search confirm consistent gains from web search, but also substantial remaining headroom. Diagnostic experiments identify semantic de-obfuscation and open-ended entity recall as key bottlenecks, and show that reasoning-centric search can outperform report-oriented agents. An 80-item finance pilot provides preliminary evidence of transfer beyond entertainment within a Chinese-language setting. Melonbench offers a challenging initial testbed for search agents under intentional obfuscation and noisy evidence. The dataset is publicly available at https://huggingface.co/datasets/janehaha/MelonBench.
Anthology ID:
2026.emnlp-main.660
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:
15202–15233
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URL:
https://aclanthology.org/2026.emnlp-main.660/
DOI:
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Cite (ACL):
Zhishan Lin, Jingxiao Li, Yanbing Zhang, Ziyan Liu, Yuqing Shao, Yunfei Tong, Ganghao Liu, Qian Zhang, and Zhe Wang. 2026. MelonBench: A Benchmark for Coded Entity Resolution over Noisy Web Evidence. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 15202–15233, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MelonBench: A Benchmark for Coded Entity Resolution over Noisy Web Evidence (Lin et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.660.pdf