X-NLP at SemEval-2026 Task 12: Prompting LLMs for Abductive Event Reasoning

Caelen Mattie, Patrick Bowen, Milton King


Abstract
In this work, we applied two different systems to the SemEval 2026 Shared Task 12, which exploresabductive event reasoning. Specifically, this task involves determining the cause of an event from a list of candidate causes. Instances are accompanied with documents that can provide applicable knowledge for the target event. Both of our systems involve prompting LLMS and our best performing system leverages retrieval-augmented generation. Our best performing system achieved a score of 84% and ranked 40th out of the 221 total submissions.
Anthology ID:
2026.semeval-1.289
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:
2281–2289
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.289/
DOI:
Bibkey:
Cite (ACL):
Caelen Mattie, Patrick Bowen, and Milton King. 2026. X-NLP at SemEval-2026 Task 12: Prompting LLMs for Abductive Event Reasoning. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 2281–2289, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
X-NLP at SemEval-2026 Task 12: Prompting LLMs for Abductive Event Reasoning (Mattie et al., SemEval 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.289.pdf
Supplementarymaterial:
 2026.semeval-1.289.SupplementaryMaterial.zip