QueryDiagramEval: Evaluating and Benchmarking LLM Diagram Generation under Noisy Conditions

Ted Zhang, Souvik Das, Kai Ni, Aditya Agrawal, Xin Guo, Denis Kochedykov


Abstract
Chat assistants increasingly ask large language models to turn free-form user prose into structured, executable diagrams. These requests are noisy user-generated text: informal, hedged, jargon-mixed, incomplete, and often describing the target only indirectly—in workflow language rather than diagram vocabulary. Evaluation is hard because many distinct diagrams satisfy the same noisy request, making reference-based metrics too rigid where no ground truth exists, while reference-free LLM judges give weak, hard-to-reproduce diagnostics. We introduce QueryDiagramEval (QDE), a reference-free protocol scoring diagram generation directly against raw, noisy queries via two levels: deterministic compilation gates (syntax, rendering, diagram-type correctness), then a semantic-fidelity layer where a multimodal auditor is grounded in type-specific structural facts parsed from the code. On 255 annotated predictions, QDE aligns strongly with holistic human ratings (𝜌=0.715), outperforming an ungrounded LLM judge. We also release MermaidBench, a source-grounded benchmark of 1,150 query–gold pairs over 11 diagram types, four query-difficulty tiers, and a multi-turn track, with the gold held fixed to isolate robustness to input-side noise. Furthermore, we conduct experiments on eight frontier-model and harnesses to show that the our agentic framework reaches near-gold quality while failures concentrate in topology preservation, label grounding, and type-specific syntax.
Anthology ID:
2026.wnut-1.18
Volume:
Proceedings of the 11th Workshop on Natural User-generated Text
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
JinYeong Bak, Rob van der Goot, Hyeju Jang, Weerayut Buaphet, Alan Ramponi, Wei Xu, Alan Ritter
Venues:
WNUT | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
244–265
Language:
URL:
https://aclanthology.org/2026.wnut-1.18/
DOI:
Bibkey:
Cite (ACL):
Ted Zhang, Souvik Das, Kai Ni, Aditya Agrawal, Xin Guo, and Denis Kochedykov. 2026. QueryDiagramEval: Evaluating and Benchmarking LLM Diagram Generation under Noisy Conditions. In Proceedings of the 11th Workshop on Natural User-generated Text, pages 244–265, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
QueryDiagramEval: Evaluating and Benchmarking LLM Diagram Generation under Noisy Conditions (Zhang et al., WNUT 2026)
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PDF:
https://aclanthology.org/2026.wnut-1.18.pdf