Closing the Gap at CRAC 2026: Two-Stage Adaptation for LLM-Based Multilingual Coreference Resolution

Antoine Bourgois, Olga Seminck, Thierry Poibeau


Abstract
We present our submission to the LLM track of the 2026 Computational Models of Reference, Anaphora and Coreference (CRAC 2026) shared task. With an average CoNLL F1 score of 74.32 on the official test set, our system ranked first in the LLM track, and third overall. Our system is based on the Gemma-3-27b model, fine-tuned using a two-stage strategy with a multilingual base adapter followed by dataset-specific adapters. We represent mention spans by their headword using an XML-inspired format with local reindexing and annotate documents iteratively. These design choices proved effective across languages, document lengths, and annotation guidelines.
Anthology ID:
2026.codi-1.23
Volume:
Proceedings of the 2nd Joint Workshop on Computational Approaches to Discourse, Context and Document-Level Inferences and Computational Models of Reference, Anaphora and Coreference (CODI-CRAC 2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Chloé Braud, Christian Hardmeier, Maciej Ogrodniczuk, Sharid Loaiciga, Amir Zeldes, Michal Novák, Chuyuan Li, Michael Strube, Junyi Jessy Li
Venues:
CODI | CRAC | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
167–183
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.codi-1.23/
DOI:
Bibkey:
Cite (ACL):
Antoine Bourgois, Olga Seminck, and Thierry Poibeau. 2026. Closing the Gap at CRAC 2026: Two-Stage Adaptation for LLM-Based Multilingual Coreference Resolution. In Proceedings of the 2nd Joint Workshop on Computational Approaches to Discourse, Context and Document-Level Inferences and Computational Models of Reference, Anaphora and Coreference (CODI-CRAC 2026), pages 167–183, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Closing the Gap at CRAC 2026: Two-Stage Adaptation for LLM-Based Multilingual Coreference Resolution (Bourgois et al., CODI-CRAC 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.codi-1.23.pdf
Supplementarymaterial:
 2026.codi-1.23.SupplementaryMaterial.zip