EXACT: Explicit Attribute-Guided Decoding-Time Personalization

Fuente: arXiv
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Main Authors: Yu, Xin, Xing, Hanwen, Xue, Lingzhou
Format: Preprint
Published: 2026
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author Yu, Xin
Xing, Hanwen
Xue, Lingzhou
author_facet Yu, Xin
Xing, Hanwen
Xue, Lingzhou
contents Achieving personalized alignment requires adapting large language models to each user's evolving context. While decoding-time personalization offers a scalable alternative to training-time methods, existing methods largely rely on implicit, less interpretable preference representations and impose a rigid, context-agnostic user representation, failing to account for how preferences shift across prompts. We introduce EXACT, a new decoding-time personalization that aligns generation with limited pairwise preference feedback using a predefined set of interpretable attributes. EXACT first identifies user-specific attribute subsets by maximizing the likelihood of preferred responses in the offline stage. Then, for online inference, EXACT retrieves the most semantically relevant attributes for an incoming prompt and injects them into the context to steer generation. We establish theoretical approximation guarantees for the proposed algorithm under mild assumptions, and provably show that our similarity-based retrieval mechanism effectively mitigates contextual preference shifts, adapting to disparate tasks without pooling conflicting preferences. Extensive experiments on human-annotated preference datasets demonstrate that EXACT consistently outperforms strong baselines, including preference modeling accuracy and personalized generation quality.
format Preprint
id arxiv_https___arxiv_org_abs_2602_17695
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle EXACT: Explicit Attribute-Guided Decoding-Time Personalization
Yu, Xin
Xing, Hanwen
Xue, Lingzhou
Machine Learning
Artificial Intelligence
Information Retrieval
Achieving personalized alignment requires adapting large language models to each user's evolving context. While decoding-time personalization offers a scalable alternative to training-time methods, existing methods largely rely on implicit, less interpretable preference representations and impose a rigid, context-agnostic user representation, failing to account for how preferences shift across prompts. We introduce EXACT, a new decoding-time personalization that aligns generation with limited pairwise preference feedback using a predefined set of interpretable attributes. EXACT first identifies user-specific attribute subsets by maximizing the likelihood of preferred responses in the offline stage. Then, for online inference, EXACT retrieves the most semantically relevant attributes for an incoming prompt and injects them into the context to steer generation. We establish theoretical approximation guarantees for the proposed algorithm under mild assumptions, and provably show that our similarity-based retrieval mechanism effectively mitigates contextual preference shifts, adapting to disparate tasks without pooling conflicting preferences. Extensive experiments on human-annotated preference datasets demonstrate that EXACT consistently outperforms strong baselines, including preference modeling accuracy and personalized generation quality.
title EXACT: Explicit Attribute-Guided Decoding-Time Personalization
topic Machine Learning
Artificial Intelligence
Information Retrieval
url https://arxiv.org/abs/2602.17695