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SemEval-2026 Task 13: Detecting Machine-Generated Code with Multiple Programming Languages, Generators, and Application Scenarios

Paper · 2026 · Daniil Orel, Dilshod Azizov, Indraneil Paul et al.

Summary

This shared task targets the problem of telling whether source code was written by people or produced by LLMs. This matters for academic integrity, hiring, and software security. Modern models can imitate human coding style, and existing detectors tend to break outside their training distribution. The organizers built a large benchmark on top of Droid and CoDet-M4. It draws on sources such as CodeNet, StarCoder-Data, Vault, TACO, LeetCode and CodeForces, and its synthetic code comes from many open model families via inverse prompting, comment- or problem-based generation, partial rewriting, and adversarial "human-like" generation. Samples were checked with ASTs and deduplicated with MinHash.

The task has three tracks:

  • Subtask A: binary detection, evaluated under language and domain shift.
  • Subtask B: attribution to a model family.
  • Subtask C: four-way labeling (human, machine, hybrid, adversarial).

Systems were ranked on Kaggle by macro-F1. Generalization to the shifted test data proved difficult for most teams. Family attribution was the hardest track, with the best score only around 0.51. The resulting resource is being extended into AICD Bench.

Key points

  • Participation: 81 teams in Subtask A, 34 in Subtask B, and 32 in Subtask C.
  • Subtask A trains only on algorithmic code in Python, Java and C++. Its test set (about 500K samples) adds C, C#, Go, JavaScript and PHP, plus research and generic deployed code.
  • Subtask B uses 11 classes: human plus 10 provider families, including DeepSeek, Qwen, Llama, IBM-Granite and OpenAI. The data covers 45 generators, and the test set includes generators unseen in training.
  • Subtask C's test set brings in out-of-distribution data:
    • human code from The Heap;
    • hybrid samples from SwallowCoder, rewritten with Llama 3.3 70B Instruct.
  • Best macro-F1 scores against the baselines:
SubtaskWinning teamBest macro-F1Baseline
ATeleAI0.9970.305
BTeleAI0.5080.229
CYoung DSMLKZ0.7850.481

In Subtask A, the next-best team reached 0.824, far behind the winner.

Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.

 Institutions

 Fields, topics and concepts

Cite

Cite as Daniil Orel, Dilshod Azizov, Indraneil Paul, Yuxia Wang, Iryna Gurevych and Preslav Nakov. 2026. SemEval-2026 Task 13: Detecting Machine-Generated Code with Multiple Programming Languages, Generators, and Application Scenarios. Proceedings of the 20th International Workshop on Semantic Evaluation (2026).

The paper itself, not this page. BibTeX from the library's record of the work. DOI 10.18653/v1/2026.semeval-1.445

@inproceedings{orel2026semeval,
  title = {{SemEval-2026 Task 13: Detecting Machine-Generated Code with Multiple Programming Languages, Generators, and Application Scenarios}},
  author = {Daniil Orel, Dilshod Azizov, Indraneil Paul, Yuxia Wang, Iryna Gurevych and Preslav Nakov},
  booktitle = {Proceedings of the 20th International Workshop on Semantic Evaluation (2026)},
  year = {2026},
  doi = {10.18653/v1/2026.semeval-1.445},
  url = {https://doi.org/10.18653/v1/2026.semeval-1.445}
}

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