GAPD: Gold-Action Policy Distillation for Agentic Reinforcement Learning in Knowledge Base Question Answering

Fuente: arXiv
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Hauptverfasser: Sun, Xin, Xie, Jianan, Chen, Zhongqi, Liu, Qiang, Wu, Shu, Song, Bowen, Wang, Weiqiang, Wang, Zilei, Wang, Liang
Format: Preprint
Veröffentlicht: 2026
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author Sun, Xin
Xie, Jianan
Chen, Zhongqi
Liu, Qiang
Wu, Shu
Song, Bowen
Wang, Weiqiang
Wang, Zilei
Wang, Liang
author_facet Sun, Xin
Xie, Jianan
Chen, Zhongqi
Liu, Qiang
Wu, Shu
Song, Bowen
Wang, Weiqiang
Wang, Zilei
Wang, Liang
contents Reinforcement learning (RL) is a natural fit for agentic knowledge base question answering (KBQA), where a model must issue executable actions, observe knowledge-base feedback, and eventually return an answer. However, current RL-based KBQA systems mainly optimize sparse rewards from the final answer, leaving intermediate action errors weakly supervised. This is especially limiting for logical-form annotated KBQA benchmarks: gold logical forms can be converted into executable action sequences, but existing pipelines use them mainly for warm-start data construction rather than for on-policy RL updates. We propose GAPD, a training-time Gold-Action Policy Distillation framework that adds dense token-level guidance to outcome-based RL. To align gold actions with on-policy student rollouts, GAPD uses MID-ANCHOR MATCHING: it treats the intermediate entities reached during student exploration and gold execution as state anchors, and matches student states to gold states through these explored entity sets. The current policy conditioned on this aligned gold action serves as a stop-gradient teacher, whose token distribution is distilled back to the ordinary student policy over generated action-token spans. GAPD consistently surpasses the current state of the art on WebQSP, GrailQA, and GraphQ.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29584
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle GAPD: Gold-Action Policy Distillation for Agentic Reinforcement Learning in Knowledge Base Question Answering
Sun, Xin
Xie, Jianan
Chen, Zhongqi
Liu, Qiang
Wu, Shu
Song, Bowen
Wang, Weiqiang
Wang, Zilei
Wang, Liang
Computation and Language
Reinforcement learning (RL) is a natural fit for agentic knowledge base question answering (KBQA), where a model must issue executable actions, observe knowledge-base feedback, and eventually return an answer. However, current RL-based KBQA systems mainly optimize sparse rewards from the final answer, leaving intermediate action errors weakly supervised. This is especially limiting for logical-form annotated KBQA benchmarks: gold logical forms can be converted into executable action sequences, but existing pipelines use them mainly for warm-start data construction rather than for on-policy RL updates. We propose GAPD, a training-time Gold-Action Policy Distillation framework that adds dense token-level guidance to outcome-based RL. To align gold actions with on-policy student rollouts, GAPD uses MID-ANCHOR MATCHING: it treats the intermediate entities reached during student exploration and gold execution as state anchors, and matches student states to gold states through these explored entity sets. The current policy conditioned on this aligned gold action serves as a stop-gradient teacher, whose token distribution is distilled back to the ordinary student policy over generated action-token spans. GAPD consistently surpasses the current state of the art on WebQSP, GrailQA, and GraphQ.
title GAPD: Gold-Action Policy Distillation for Agentic Reinforcement Learning in Knowledge Base Question Answering
topic Computation and Language
url https://arxiv.org/abs/2605.29584