QueStER: Query Specification for Generative Keyword-Based Retrieval

Arthur Satouf, Yuxuan Zong, Habiboulaye Amadou Boubacar, Pablo Piantanida, Benjamin Piwowarski


Abstract
Generative retrieval (GR) differs from the traditional index–then–retrieve pipeline by storing relevance in model parameters and generating retrieval cues directly from the query, but it can be brittle out of domain and expensive to scale. We introduce QueStER (QUEry SpecificaTion for gEnerative Keyword-Based Retrieval), which bridges GR and query reformulation by learning to generate explicit keyword-based search specifications. Given a user query, a lightweight LLM produces a keyword query that is executed by a standard retriever (BM25), combining the generalization benefits of generative query rewriting with the efficiency and scalability of lexical indexing. We train the rewriting policy with reinforcement learning techniques. Across in- and out-of-domain evaluations, QueStER consistently improves over BM25 and is competitive with neural IR baselines, while maintaining strong efficiency.
Anthology ID:
2026.findings-eacl.312
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
5957–5968
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.312/
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Cite (ACL):
Arthur Satouf, Yuxuan Zong, Habiboulaye Amadou Boubacar, Pablo Piantanida, and Benjamin Piwowarski. 2026. QueStER: Query Specification for Generative Keyword-Based Retrieval. In Findings of the Association for Computational Linguistics: EACL 2026, pages 5957–5968, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
QueStER: Query Specification for Generative Keyword-Based Retrieval (Satouf et al., Findings 2026)
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