Learning When Not to Act: Mitigating Tool Abuse in Agentic Reinforcement Learning

Fuente: arXiv
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Auteurs principaux: Chen, Liuji, Tang, Dianxing, Shi, Xing, Chen, Dingshuo, Liu, Qiang, Wu, Shu, Wang, Liang
Format: Preprint
Publié: 2026
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author Chen, Liuji
Tang, Dianxing
Shi, Xing
Chen, Dingshuo
Liu, Qiang
Wu, Shu
Wang, Liang
author_facet Chen, Liuji
Tang, Dianxing
Shi, Xing
Chen, Dingshuo
Liu, Qiang
Wu, Shu
Wang, Liang
contents Agentic reinforcement learning can induce tool abuse, where models overuse external tools even for queries solvable by internal reasoning. Existing approaches mitigate this issue with uniform tool-use penalties or hard limits, which reduce tool frequency but may also suppress useful tool-assisted exploration. We propose EAPO, an Efficient Agentic Policy Optimization framework that learns selective tool use. EAPO introduces tool-free trajectories into each rollout group, applies difficulty-aware reward shaping to penalize redundant tool calls mainly on easier queries, and uses confidence-aware token reweighting to improve policy learning. Across nine mathematical and knowledge-intensive reasoning benchmarks, EAPO consistently improves the accuracy efficiency trade-off on Qwen2.5-3B, Qwen2.5-7B, and Llama3.1-8B. Compared with GRPO, EAPO improves average performance by 10.45%, 7.27%, and 9.69%, while reducing average tool calls by 18.33%, 18.33%, and 24.59%, respectively. These results show that agents can learn when not to use tools without compromising tool-integrated reasoning.
format Preprint
id arxiv_https___arxiv_org_abs_2606_02132
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Learning When Not to Act: Mitigating Tool Abuse in Agentic Reinforcement Learning
Chen, Liuji
Tang, Dianxing
Shi, Xing
Chen, Dingshuo
Liu, Qiang
Wu, Shu
Wang, Liang
Artificial Intelligence
Agentic reinforcement learning can induce tool abuse, where models overuse external tools even for queries solvable by internal reasoning. Existing approaches mitigate this issue with uniform tool-use penalties or hard limits, which reduce tool frequency but may also suppress useful tool-assisted exploration. We propose EAPO, an Efficient Agentic Policy Optimization framework that learns selective tool use. EAPO introduces tool-free trajectories into each rollout group, applies difficulty-aware reward shaping to penalize redundant tool calls mainly on easier queries, and uses confidence-aware token reweighting to improve policy learning. Across nine mathematical and knowledge-intensive reasoning benchmarks, EAPO consistently improves the accuracy efficiency trade-off on Qwen2.5-3B, Qwen2.5-7B, and Llama3.1-8B. Compared with GRPO, EAPO improves average performance by 10.45%, 7.27%, and 9.69%, while reducing average tool calls by 18.33%, 18.33%, and 24.59%, respectively. These results show that agents can learn when not to use tools without compromising tool-integrated reasoning.
title Learning When Not to Act: Mitigating Tool Abuse in Agentic Reinforcement Learning
topic Artificial Intelligence
url https://arxiv.org/abs/2606.02132