FMISUYotkovaKastreva at SemEval-2026 Task 13: Lightweight Detection of LLM-Generated Code via Stylometric Signals

Elitsa Yotkova, Violeta Kastreva, Dimitar Dimitrov, Ivan Koychev, Preslav Nakov


Abstract
SemEval-2026 Task 13 investigates machine-generated code detection across multiple programming languages and application scenarios, asking participating systems to generalize to unseen languages and domains. This paper describes our participation in Subtask A (binary classification) and explores both pretrained code encoders and lightweight feature-based methods.We design ratio-based features that are less sensitive to snippet length. To support the extraction of descriptiveness-related signals, we use parsing engines and a programming-language classifier. Additionally, we train a separate code-vs-text line classifier to identify raw natural language segments embedded within samples. We combine a shallow decision tree with heuristic rules derived from data analysis to produce the final predictions. Our approach is computationally efficient, requires only CPU resources for training, and achieves near-instant inference time, offering a lightweight alternative to large pretrained models.
Anthology ID:
2026.semeval-1.275
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2179–2186
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.275/
DOI:
Bibkey:
Cite (ACL):
Elitsa Yotkova, Violeta Kastreva, Dimitar Dimitrov, Ivan Koychev, and Preslav Nakov. 2026. FMISUYotkovaKastreva at SemEval-2026 Task 13: Lightweight Detection of LLM-Generated Code via Stylometric Signals. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 2179–2186, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
FMISUYotkovaKastreva at SemEval-2026 Task 13: Lightweight Detection of LLM-Generated Code via Stylometric Signals (Yotkova et al., SemEval 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.275.pdf
Supplementarymaterial:
 2026.semeval-1.275.SupplementaryMaterial.zip