ML2B: Benchmarking LLMs on Cross-Lingual ML Pipeline Generation

We introduce ML2B, the first benchmark for evaluating cross-lingual task comprehension in end-to-end ML pipeline generation by large language models. Despite growing global AI adoption, no systematic evaluation exists for ML pipeline generation beyond English task descriptions. ML2B addresses this gap with 35 Kaggle competitions spanning tabular, text, and image domains, translated into 14 languages by native-speaker researchers with ML expertise, yielding 490 task-language pairs. To ensure evaluation integrity, the benchmark incorporates 10 private competitions without publicly available solutions and employs network-isolated evaluation infrastructure restricting runtime access to essential ML resources. We provide standardized evaluation protocols, an AutoGluon algorithmic baseline, and comprehensive failure mode analysis. Experiments with frontier models (GPT-4.1-mini, GPT-OSS-120b, Gemini-2.5-Flash) reveal that cross-lingual performance degradation is highly task-dependent rather than following traditional resource-availability hierarchies, with gaps ranging from language advantages to severe degradation depending on competition characteristics. These findings challenge conventional assumptions about multilingual model capabilities and underscore the necessity of systematic cross-lingual evaluation for ML pipeline generation. We open-source the benchmark, baselines, and evaluation infrastructure at https://github.com/enaix/ml2b.