Team Duo at SemEval-2026 Task 13: Fine-tuning CodeBERT for Out-of-Distribution AI-Generated Code Detection

Subhiksha G, Sanjai M, Rajalakshmi Sivanaiah, Angel Deborah S


Abstract
This paper addresses detecting AI-generated code in out-of-distribution settings by fine-tuning CodeBERT on algorithmic code from C++, Python, and Java. While the model achieves near-perfect performance on training data (F1 = 0.9935), it degrades significantly on unseen languages and domains (F1 = 0.3532). The high recall (0.8789) but low precision (0.2210) indicates over-prediction of machine-generated code. Error analysis reveals three failure modes: domain mismatch, unfamiliar syntax patterns, and insufficient training. Multi-epoch training and domain-specific augmentation are needed to improve OOD generalization.
Anthology ID:
2026.semeval-1.265
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:
2104–2107
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.265/
DOI:
Bibkey:
Cite (ACL):
Subhiksha G, Sanjai M, Rajalakshmi Sivanaiah, and Angel Deborah S. 2026. Team Duo at SemEval-2026 Task 13: Fine-tuning CodeBERT for Out-of-Distribution AI-Generated Code Detection. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 2104–2107, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Team Duo at SemEval-2026 Task 13: Fine-tuning CodeBERT for Out-of-Distribution AI-Generated Code Detection (G et al., SemEval 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.265.pdf