ENSAR at AraSeg Shared Task 2026: An Ensemble of Encoders With Agentic Error Refinement

Noor Emam, Omar Mokhtar Gaber Saqr, Mostafa Gaafar, Ali Elaswad


Abstract
We describe ENSAR, our submission to the AraSeg 2026 shared task on Arabic sentence segmentation, where a system must decide, for every word in a document, whether a sentence ends there. The four tracks strip punctuation, paragraph breaks, both, or neither. We start from an ensemble of five fine-tuned encoders decoded with a length-aware semi-Markov program. It is strong, but most of its mistakes are places where all five models are wrong and all five assign high confidence, so averaging them or moving a threshold changes nothing. ENSAR adds a reasoning stage on top. Two LLM juries, each holding a written policy learned from its own graded errors on the training split, debate every document and apply only the edits both endorse. Our system ranked first on three of the four tracks in both the closed and open settings.
Anthology ID:
2026.arabicnlp-sharedtasks.117
Volume:
Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Muhammad Abdul-Mageed, Tamer Elsayed, Houda Bouamor, Samhaa El-Beltagy, Hend Al-Khalifa, Ahmed Abdelali, AbdelRahim Elmadany, Abdellah El Mekki, Kareem Darwish, Sakhar Alkhereyf, Hamzah Luqman, Salam Khalifa, Samar Magdy, Zaid Alyafeai, Injy Hamed, Wajdi Zaghouani, Imed Zitouni
Venue:
ArabicNLP
SIG:
SIGARAB
Publisher:
Association for Computational Linguistics
Note:
Pages:
944–955
Language:
URL:
https://aclanthology.org/2026.arabicnlp-sharedtasks.117/
DOI:
Bibkey:
Cite (ACL):
Noor Emam, Omar Mokhtar Gaber Saqr, Mostafa Gaafar, and Ali Elaswad. 2026. ENSAR at AraSeg Shared Task 2026: An Ensemble of Encoders With Agentic Error Refinement. In Proceedings of The Fourth Arabic Natural Language Processing Conference: Shared Tasks, pages 944–955, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ENSAR at AraSeg Shared Task 2026: An Ensemble of Encoders With Agentic Error Refinement (Emam et al., ArabicNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.arabicnlp-sharedtasks.117.pdf