RubricEM: Meta-RL with Rubric-guided Policy Decomposition beyond Verifiable Rewards

Fuente: arXiv
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Autori principali: Li, Gaotang, Mishra, Bhavana Dalvi, Wang, Zifeng, Yan, Jun, Chen, Yanfei, Li, Chun-Liang, Le, Long T., Han, Rujun, Lee, George, Tong, Hanghang, Lee, Chen-Yu, Pfister, Tomas
Natura: Preprint
Pubblicazione: 2026
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author Li, Gaotang
Mishra, Bhavana Dalvi
Wang, Zifeng
Yan, Jun
Chen, Yanfei
Li, Chun-Liang
Le, Long T.
Han, Rujun
Lee, George
Tong, Hanghang
Lee, Chen-Yu
Pfister, Tomas
author_facet Li, Gaotang
Mishra, Bhavana Dalvi
Wang, Zifeng
Yan, Jun
Chen, Yanfei
Li, Chun-Liang
Le, Long T.
Han, Rujun
Lee, George
Tong, Hanghang
Lee, Chen-Yu
Pfister, Tomas
contents Training deep research agents, namely systems that plan, search, evaluate evidence, and synthesize long-form reports, pushes reinforcement learning beyond the regime of verifiable rewards. Their outputs lack ground-truth answers, their trajectories span many tool-augmented decisions, and standard post-training offers little mechanism for turning past attempts into reusable experience. In this work, we argue that rubrics should serve not merely as final-answer evaluators, but as the shared interface that structures policy execution, judge feedback, and agent memory. Based on this view, we introduce RubricEM, a rubric-guided reinforcement learning framework that combines stagewise policy decomposition with reflection-based meta-policy evolution. RubricEM first makes research trajectories stage-aware by conditioning planning, evidence gathering, review, and synthesis on self-generated rubrics. It then assigns credit with Stage-Structured GRPO, which uses stagewise rubric judgments to provide denser semantic feedback for long-horizon optimization. In parallel, RubricEM trains a shared-backbone reflection meta-policy that distills judged trajectories into reusable rubric-grounded guidance for future attempts. The resulting RubricEM-8B achieves strong performance across four long-form research benchmarks, outperforming comparable open models and approaching proprietary deep-research systems. Beyond final performance, we perform thorough analyses to understand the key ingredients of RubricEM.
format Preprint
id arxiv_https___arxiv_org_abs_2605_10899
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle RubricEM: Meta-RL with Rubric-guided Policy Decomposition beyond Verifiable Rewards
Li, Gaotang
Mishra, Bhavana Dalvi
Wang, Zifeng
Yan, Jun
Chen, Yanfei
Li, Chun-Liang
Le, Long T.
Han, Rujun
Lee, George
Tong, Hanghang
Lee, Chen-Yu
Pfister, Tomas
Computation and Language
Machine Learning
Training deep research agents, namely systems that plan, search, evaluate evidence, and synthesize long-form reports, pushes reinforcement learning beyond the regime of verifiable rewards. Their outputs lack ground-truth answers, their trajectories span many tool-augmented decisions, and standard post-training offers little mechanism for turning past attempts into reusable experience. In this work, we argue that rubrics should serve not merely as final-answer evaluators, but as the shared interface that structures policy execution, judge feedback, and agent memory. Based on this view, we introduce RubricEM, a rubric-guided reinforcement learning framework that combines stagewise policy decomposition with reflection-based meta-policy evolution. RubricEM first makes research trajectories stage-aware by conditioning planning, evidence gathering, review, and synthesis on self-generated rubrics. It then assigns credit with Stage-Structured GRPO, which uses stagewise rubric judgments to provide denser semantic feedback for long-horizon optimization. In parallel, RubricEM trains a shared-backbone reflection meta-policy that distills judged trajectories into reusable rubric-grounded guidance for future attempts. The resulting RubricEM-8B achieves strong performance across four long-form research benchmarks, outperforming comparable open models and approaching proprietary deep-research systems. Beyond final performance, we perform thorough analyses to understand the key ingredients of RubricEM.
title RubricEM: Meta-RL with Rubric-guided Policy Decomposition beyond Verifiable Rewards
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2605.10899