METAL: A Multi-Agent Framework for Chart Generation with Test-Time Scaling

Bingxuan Li, Yiwei Wang, Jiuxiang Gu, Kai-Wei Chang, and Nanyun Peng, in Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (ACL) , 2025 .

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Abstract

Chart generation aims to generate code to produce charts satisfying the desired visual properties, e.g., texts, layout, color, and type. It has great potential to empower the automatic professional report generation in financial analysis, research presentation, education, and healthcare. In this work, we build a vision-language model (VLM) based multi-agent framework for effective automatic chart generation. Generating high-quality charts requires both strong visual design skills and precise coding capabilities that embed the desired visual properties into code. Such a complex multi-modal reasoning process is difficult for direct prompting of VLMs. To resolve these challenges, we propose METAL, a multi-agent framework that decomposes the task of chart generation into the iterative collaboration among specialized agents. METAL achieves a 5.2% improvement in the F1 score over the current best result in the chart generation task. Additionally, METAL improves chart generation performance by 11.33% over Direct Prompting with LLaMA-3.2-11B. Furthermore, the METAL framework exhibits the phenomenon of test-time scaling: its performance increases monotonically as the logarithm of computational budget grows from 512 to 8192 tokens.

Bib Entry

@inproceedings{li2025metal,
  title = { METAL: A Multi-Agent Framework for Chart Generation with Test-Time Scaling },
  author = {Li, Bingxuan and Wang, Yiwei and Gu, Jiuxiang and Chang, Kai-Wei and Peng, Nanyun},
  year = { 2025 },
  booktitle = { Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (ACL) }
}