@inproceedings{villate-lemus-2026-lafed,
title = "{LAFED} at {S}em{E}val-2026 Task 13: Language-Agnostic Feature Engineering for Cross-Lingual {AI}-Generated Code Detection",
author = "Villate Lemus, Juan",
editor = "Kochmar, Ekaterina and
Ghosh, Debanjan and
North, Kai and
Komachi, Mamoru",
booktitle = "Proceedings of the 20th {I}nternational {W}orkshop on {S}emantic {E}valuation (2026)",
month = jul,
year = "2026",
address = "San Diego, California, USA",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2026.semeval-1.9/",
pages = "59--64",
ISBN = "979-8-89176-414-9",
abstract = "Robust detection of AI-generated source code across programming languages remains challenging due to language-specific cues and train{--}test distribution shifts. We present LAFED (Language-Agnostic Feature Engineering Detector), a feature-engineering approach trained on {\{}Python, Java, C++{\}} and evaluated on a multilingual test set that includes unseen languages {\{}C, C{\#}, Go, JavaScript, PHP{\}}. LAFED combines (i) structural skeletal features (indentation, control-flow density, and approximations of McCabe/Halstead complexity), (ii) character and whitespace statistics inspired by stylometry, and (iii) micro-style patterns (operator spacing, blank lines, indentation consistency). Using XGBoost (Chen and Guestrin, 2016) with Optuna hyperparameter search (Akiba et al., 2019), our best model achieves macro-F1=0.7570 on a 1,000-sample test set; the official submission obtains macro-F1=0.75209 (5th place in Subtask A). Per-language analysis shows strong transfer to C{\#} (0.7753) and JavaScript (0.7683), but weaker performance on Go (0.6400) and PHP (0.5238)."
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<abstract>Robust detection of AI-generated source code across programming languages remains challenging due to language-specific cues and train–test distribution shifts. We present LAFED (Language-Agnostic Feature Engineering Detector), a feature-engineering approach trained on {Python, Java, C++} and evaluated on a multilingual test set that includes unseen languages {C, C#, Go, JavaScript, PHP}. LAFED combines (i) structural skeletal features (indentation, control-flow density, and approximations of McCabe/Halstead complexity), (ii) character and whitespace statistics inspired by stylometry, and (iii) micro-style patterns (operator spacing, blank lines, indentation consistency). Using XGBoost (Chen and Guestrin, 2016) with Optuna hyperparameter search (Akiba et al., 2019), our best model achieves macro-F1=0.7570 on a 1,000-sample test set; the official submission obtains macro-F1=0.75209 (5th place in Subtask A). Per-language analysis shows strong transfer to C# (0.7753) and JavaScript (0.7683), but weaker performance on Go (0.6400) and PHP (0.5238).</abstract>
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%0 Conference Proceedings
%T LAFED at SemEval-2026 Task 13: Language-Agnostic Feature Engineering for Cross-Lingual AI-Generated Code Detection
%A Villate Lemus, Juan
%Y Kochmar, Ekaterina
%Y Ghosh, Debanjan
%Y North, Kai
%Y Komachi, Mamoru
%S Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
%D 2026
%8 July
%I Association for Computational Linguistics
%C San Diego, California, USA
%@ 979-8-89176-414-9
%F villate-lemus-2026-lafed
%X Robust detection of AI-generated source code across programming languages remains challenging due to language-specific cues and train–test distribution shifts. We present LAFED (Language-Agnostic Feature Engineering Detector), a feature-engineering approach trained on {Python, Java, C++} and evaluated on a multilingual test set that includes unseen languages {C, C#, Go, JavaScript, PHP}. LAFED combines (i) structural skeletal features (indentation, control-flow density, and approximations of McCabe/Halstead complexity), (ii) character and whitespace statistics inspired by stylometry, and (iii) micro-style patterns (operator spacing, blank lines, indentation consistency). Using XGBoost (Chen and Guestrin, 2016) with Optuna hyperparameter search (Akiba et al., 2019), our best model achieves macro-F1=0.7570 on a 1,000-sample test set; the official submission obtains macro-F1=0.75209 (5th place in Subtask A). Per-language analysis shows strong transfer to C# (0.7753) and JavaScript (0.7683), but weaker performance on Go (0.6400) and PHP (0.5238).
%U https://aclanthology.org/2026.semeval-1.9/
%P 59-64Markdown (Informal)
[LAFED at SemEval-2026 Task 13: Language-Agnostic Feature Engineering for Cross-Lingual AI-Generated Code Detection](https://aclanthology.org/2026.semeval-1.9/) (Villate Lemus, SemEval 2026)
ACL