MatchTIR: Fine-Grained Supervision for Tool-Integrated Reasoning via Bipartite Matching

Fuente: arXiv
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Auteurs principaux: Qu, Changle, Dai, Sunhao, Cai, Hengyi, Xu, Jun, Wang, Shuaiqiang, Yin, Dawei
Format: Preprint
Publié: 2026
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author Qu, Changle
Dai, Sunhao
Cai, Hengyi
Xu, Jun
Wang, Shuaiqiang
Yin, Dawei
author_facet Qu, Changle
Dai, Sunhao
Cai, Hengyi
Xu, Jun
Wang, Shuaiqiang
Yin, Dawei
contents Tool-Integrated Reasoning (TIR) empowers large language models (LLMs) to tackle complex tasks by interleaving reasoning steps with external tool interactions. However, existing reinforcement learning methods typically rely on outcome- or trajectory-level rewards, assigning uniform advantages to all steps within a trajectory. This coarse-grained credit assignment fails to distinguish effective tool calls from redundant or erroneous ones, particularly in long-horizon multi-turn scenarios. To address this, we propose MatchTIR, a framework that introduces fine-grained supervision via bipartite matching-based turn-level reward assignment and dual-level advantage estimation. Specifically, we formulate credit assignment as a bipartite matching problem between predicted and ground-truth traces, utilizing two assignment strategies to derive dense turn-level rewards. Furthermore, to balance local step precision with global task success, we introduce a dual-level advantage estimation scheme that integrates turn-level and trajectory-level signals, assigning distinct advantage values to individual interaction turns. Extensive experiments on three benchmarks demonstrate the superiority of MatchTIR. Notably, our 4B model surpasses the majority of 8B competitors, particularly in long-horizon and multi-turn tasks. Our codes are available at https://github.com/quchangle1/MatchTIR.
format Preprint
id arxiv_https___arxiv_org_abs_2601_10712
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle MatchTIR: Fine-Grained Supervision for Tool-Integrated Reasoning via Bipartite Matching
Qu, Changle
Dai, Sunhao
Cai, Hengyi
Xu, Jun
Wang, Shuaiqiang
Yin, Dawei
Computation and Language
Artificial Intelligence
Tool-Integrated Reasoning (TIR) empowers large language models (LLMs) to tackle complex tasks by interleaving reasoning steps with external tool interactions. However, existing reinforcement learning methods typically rely on outcome- or trajectory-level rewards, assigning uniform advantages to all steps within a trajectory. This coarse-grained credit assignment fails to distinguish effective tool calls from redundant or erroneous ones, particularly in long-horizon multi-turn scenarios. To address this, we propose MatchTIR, a framework that introduces fine-grained supervision via bipartite matching-based turn-level reward assignment and dual-level advantage estimation. Specifically, we formulate credit assignment as a bipartite matching problem between predicted and ground-truth traces, utilizing two assignment strategies to derive dense turn-level rewards. Furthermore, to balance local step precision with global task success, we introduce a dual-level advantage estimation scheme that integrates turn-level and trajectory-level signals, assigning distinct advantage values to individual interaction turns. Extensive experiments on three benchmarks demonstrate the superiority of MatchTIR. Notably, our 4B model surpasses the majority of 8B competitors, particularly in long-horizon and multi-turn tasks. Our codes are available at https://github.com/quchangle1/MatchTIR.
title MatchTIR: Fine-Grained Supervision for Tool-Integrated Reasoning via Bipartite Matching
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2601.10712