Dream at SemEval-2026 Task 13: SALSA for Single-Pass Machine-Generated Code Detection

Ruslan Berdichevsky, Shai Nahum-Gefen, Elad Ben-Zaken


Abstract
Large language models have transformed code generation, raising concerns around authorship, assessment integrity, and software trust. SemEval-2026 Task 13 Subtask A operationalizes detection as binary classification over code snippets, with a particular emphasis on out-of-distribution (OOD) generalization across unseen programming languages and application domains. We propose a SALSA-style formulation, Single-pass Autoregressive LLM Structured Classification, that maps each class to a dedicated output token and trains the model to emit a single-token label in a structured response. Rather than engineering hand-crafted features or decision rules, this formulation delegates the authorship decision to the model. To improve OOD robustness, we combine balanced sampling across languages with parameter-efficient fine-tuning and conservative training (low learning rate, single epoch) to avoid overfitting to the training domain. Our best system achieves OOD F1 = 0.789 on the official leaderboard, substantially outperforming the CodeBERT baseline (F1 = 0.305).
Anthology ID:
2026.semeval-1.52
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:
354–360
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.52/
DOI:
Bibkey:
Cite (ACL):
Ruslan Berdichevsky, Shai Nahum-Gefen, and Elad Ben-Zaken. 2026. Dream at SemEval-2026 Task 13: SALSA for Single-Pass Machine-Generated Code Detection. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 354–360, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Dream at SemEval-2026 Task 13: SALSA for Single-Pass Machine-Generated Code Detection (Berdichevsky et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.52.pdf
Supplementarymaterial:
 2026.semeval-1.52.SupplementaryMaterial.zip