contestant001 at SemEval-2026 Task 13 Stylometric and TF-IDF-Based Detection of Machine-Generated Code

Bora Ozaylar


Abstract
Reliable detection of machine-generated codehas become increasingly important for aca-demic integrity and software quality as codegeneration is largely being undertaken by largelanguage models. This paper presents our ap-proach to SemEval-2026 Task 13, Subtask A:detecting machine-generated code in a binaryclassification setting, where we propose anensemble approach combining TF-IDF lexi-cal representations with 23 hand-crafted sty-lometric features for binary classification ofAI-generated code. Our system aims to addressthe challenge of cross-language generalizationby extracting language-agnostic patterns andcombining them with TF-IDF. While we ob-served that transformer-based models (Code-BERT, UniXcoder) noticeably underperformedunder distribution shift, our analysis revealedthat AI-generated code exhibits distinct sty-lometric patterns and our TF-IDF ensembleachieved 0.5175 Macro F1 on the task submis-sion.
Anthology ID:
2026.semeval-1.391
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:
3124–3129
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.391/
DOI:
Bibkey:
Cite (ACL):
Bora Ozaylar. 2026. contestant001 at SemEval-2026 Task 13 Stylometric and TF-IDF-Based Detection of Machine-Generated Code. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 3124–3129, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
contestant001 at SemEval-2026 Task 13 Stylometric and TF-IDF-Based Detection of Machine-Generated Code (Ozaylar, SemEval 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.391.pdf