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arXiv · 2607.17524

Token-Level Off-Policy Learning for Faithful Generation Under Distribution Shift

Zitong Huang·Gustavo Lucas Carvalho·Deqing Fu·Robin Jia
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Abstract

We propose Token-Level Off-Policy Labeling (TOPL), an off-policy training paradigm that reframes post-training as a token-level correctness prediction task. Our key intuition is that by training the model to distinguish good and bad tokens in a response, we naturally guide the model towards generating good tokens, while avoiding the pitfalls that come with directly training the model to generate off-policy tokens. Experiments on document summarization tasks show that TOPL achieves strong out-of-distribution generalization across 11 datasets against a diverse set of sequence-level and token-level baselines. We further demonstrate that TOPL transfers effectively to machine translation, suggesting that its benefits generalize across different faithful generation tasks. Through ablation studies, we confirm that our token-level learning signal is critical to good performance; sequence-level analogues do not confer similar benefits. Finally, we show that TOPL induces interpretable model updates: the LoRA adapters learned through TOPL function as linear classification heads and steering vectors.

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Zitong Huang, Gustavo Lucas Carvalho, Deqing Fu, Robin Jia. 2026-07-20. Token-Level Off-Policy Learning for Faithful Generation Under Distribution Shift. https://arxiv.org/abs/2607.17524

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