FABLE: Fine-grained Fact Anchoring for Unstructured Model Editing

Peng Wang, Biyu Zhou, Xuehai Tang, Jizhong Han, Songlin Hu


Abstract
Unstructured model editing aims to update models with real-world text, yet existing methods often memorize text holistically without reliable fine-grained fact access. To address this, we propose FABLE, a hierarchical framework that decouples fine-grained fact injection from holistic text generation. FABLE follows a two-stage, fact-first strategy: discrete facts are anchored in shallow layers, followed by minimal updates to deeper layers to produce coherent text. This decoupling resolves the mismatch between holistic recall and fine-grained fact access, reflecting the unidirectional Transformer flow in which surface-form generation amplifies rather than corrects underlying fact representations. We also introduce UnFine, a diagnostic benchmark with fine-grained question–answer pairs and fact-level metrics for systematic evaluation. Experiments show that FABLE substantially improves fine-grained question answering while maintaining state-of-the-art holistic editing performance. Our code is publicly available at https://anonymous.4open.science/r/FABLE-B59E.
Anthology ID:
2026.findings-acl.714
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
14549–14567
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.714/
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Cite (ACL):
Peng Wang, Biyu Zhou, Xuehai Tang, Jizhong Han, and Songlin Hu. 2026. FABLE: Fine-grained Fact Anchoring for Unstructured Model Editing. In Findings of the Association for Computational Linguistics: ACL 2026, pages 14549–14567, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
FABLE: Fine-grained Fact Anchoring for Unstructured Model Editing (Wang et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.714.pdf
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