RICE-PO: Turning Retrieval Interactions into Credit Signals for Reasoning Agents

Fuente: arXiv
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Main Authors: Li, Mingchen, Zeng, Hansi, Qian, Zhuo, Huang, Jiatan, Zamani, Hamed, Yu, Hong
Format: Preprint
Published: 2026
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author Li, Mingchen
Zeng, Hansi
Qian, Zhuo
Huang, Jiatan
Zamani, Hamed
Yu, Hong
author_facet Li, Mingchen
Zeng, Hansi
Qian, Zhuo
Huang, Jiatan
Zamani, Hamed
Yu, Hong
contents Retrieval is increasingly moving from one-shot matching toward interactive reasoning, where language agents iteratively inspect evidence, reformulate queries, and search again. Training such agents raises a credit-assignment challenge: executable actions such as queries or summaries can be directly evaluated by the retriever, while latent reasoning steps are not directly observable and only affect future executable actions. This asymmetry makes outcome-level reward assignment unreliable, as the same final reward may credit reasoning steps that did not actually shape retrieval success. We propose RICE-PO, a critic-free policy optimization framework that converts retrieval interactions into localized learning signals. RICE-PO selects high-uncertainty executable actions as anchors, evaluates local counterfactual branches using retrieval metrics, and propagates credit to latent reasoning steps only when reasoning-to-action influence is strong and future residual effects are stable. On BRIGHT and BEIR, RICE-PO consistently outperforms prompt-based agents and group-based RL baselines under the same retriever setting. These results show that the structure of agent-environment interaction itself can provide useful supervision for training reasoning-based retrieval agents.
format Preprint
id arxiv_https___arxiv_org_abs_2605_26352
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle RICE-PO: Turning Retrieval Interactions into Credit Signals for Reasoning Agents
Li, Mingchen
Zeng, Hansi
Qian, Zhuo
Huang, Jiatan
Zamani, Hamed
Yu, Hong
Computation and Language
Retrieval is increasingly moving from one-shot matching toward interactive reasoning, where language agents iteratively inspect evidence, reformulate queries, and search again. Training such agents raises a credit-assignment challenge: executable actions such as queries or summaries can be directly evaluated by the retriever, while latent reasoning steps are not directly observable and only affect future executable actions. This asymmetry makes outcome-level reward assignment unreliable, as the same final reward may credit reasoning steps that did not actually shape retrieval success. We propose RICE-PO, a critic-free policy optimization framework that converts retrieval interactions into localized learning signals. RICE-PO selects high-uncertainty executable actions as anchors, evaluates local counterfactual branches using retrieval metrics, and propagates credit to latent reasoning steps only when reasoning-to-action influence is strong and future residual effects are stable. On BRIGHT and BEIR, RICE-PO consistently outperforms prompt-based agents and group-based RL baselines under the same retriever setting. These results show that the structure of agent-environment interaction itself can provide useful supervision for training reasoning-based retrieval agents.
title RICE-PO: Turning Retrieval Interactions into Credit Signals for Reasoning Agents
topic Computation and Language
url https://arxiv.org/abs/2605.26352