SRR-Judge: Step-Level Rating and Refinement for Enhancing Search-Integrated Reasoning in Search Agents
Chen Zhang, Kuicai Dong, Dexun Li, Wenjun Li, Qu Yang, Wei Han, Yong Liu
TL;DR
SRR-Judge addresses the lack of intermediate-step supervision in deep-search agents by introducing a step-level evaluator that scores and refines each thought–action pair within long-horizon trajectories. Integrated into a ReAct-based rate-and-refine workflow, it distills judgment capabilities from a large agentic model to a smaller, efficient judge (QwQ-32B), enabling both inference-time refinements and offline trajectory alignment via iterative rejection sampling. The approach demonstrates strong correlations between step-level ratings and final trajectory correctness, and yields substantial improvements in pass@1 across multiple real-world benchmarks when used for alignment, outperforming outcome-only supervision in several settings. These results highlight the practical value of step-level supervision for reliable search-integrated reasoning and scalable post-training improvement of agentic systems.
Abstract
Recent deep search agents built on large reasoning models (LRMs) excel at complex question answering by iteratively planning, acting, and gathering evidence, a capability known as search-integrated reasoning. However, mainstream approaches often train this ability using only outcome-based supervision, neglecting the quality of intermediate thoughts and actions. We introduce SRR-Judge, a framework for reliable step-level assessment of reasoning and search actions. Integrated into a modified ReAct-style rate-and-refine workflow, SRR-Judge provides fine-grained guidance for search-integrated reasoning and enables efficient post-training annotation. Using SRR-annotated data, we apply an iterative rejection sampling fine-tuning procedure to enhance the deep search capability of the base agent. Empirically, SRR-Judge delivers more reliable step-level evaluations than much larger models such as DeepSeek-V3.1, with its ratings showing strong correlation with final answer correctness. Moreover, aligning the policy with SRR-Judge annotated trajectories leads to substantial performance gains, yielding over a 10 percent average absolute pass@1 improvement across challenging deep search benchmarks.
