Repurposing Synthetic Data for Fine-grained Search Agent Supervision
Authors: name: Yida Zhao, name: Kuan Li, name: Xixi Wu, name: Liwen Zhang, name: Dingchu Zhang, name: Baixuan Li, name: Maojia Song, name: Zhuo Chen, name: Chenxi Wang, name: Xinyu Wang, name: Kewei Tu, name: Pengjun Xie, name: Jingren Zhou, name: Yong Jiang
Organization: TongyiLab

LLM-based search agents are increasingly trained on entity-centric synthetic
data to solve complex, knowledge-intensive tasks. However, prevailing training
methods like Group Relative Policy Optimization (GRPO) discard this rich entity
information, relying instead on sparse, outcome-based rewards. This critical
limitation renders them unable to distinguish informative "near-miss"
samples-those with substantially correct reasoning but a flawed final
answer-from complete failures, thus discarding valuable learning signals. We
address this by leveraging the very entities discarded during training. Our
empirical analysis reveals a strong positive correlation between the number of
ground-truth entities identified during an agent's reasoning process and final
answer accuracy. Building on this insight, we introduce Entity-aware Group
Relative Policy Optimization (E-GRPO), a novel framework that formulates a
dense entity-aware reward function. E-GRPO assigns partial rewards to incorrect
samples proportional to their entity match rate, enabling the model to
effectively learn from these "near-misses". Experiments on diverse
question-answering (QA) and deep research benchmarks show that E-GRPO
consistently and significantly outperforms the GRPO baseline. Furthermore, our
analysis reveals that E-GRPO not only achieves superior accuracy but also
induces more efficient reasoning policies that require fewer tool calls,
demonstrating a more effective and sample-efficient approach to aligning search
agents.