Tool-Star-Qwen-1.5B

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frameworks:

• Pytorch license: mit tasks:
• text-generation language:
• en metrics:
• accuracy base_model:
• Qwen/Qwen2.5-1.5B-Instruct

Model Card for Tool-Star

This is the official checkpoint we trained using the tool-star framework, based on Qwen2.5-1.5B-Instruct.

Huggingface Paper: https://huggingface.co/papers/2505.16410

Details please refer to https://github.com/dongguanting/Tool-Star

Paper title and link

The model was presented in the paper Tool-Star: Empowering LLM-Brained Multi-Tool Reasoner via Reinforcement Learning.

Paper abstract

The abstract of the paper is the following:

Recently, large language models (LLMs) have shown remarkable reasoning capabilities via large-scale reinforcement learning (RL). However, leveraging the RL algorithm to empower effective multi-tool collaborative reasoning in LLMs remains an open challenge. In this paper, we introduce Tool-Star, an RL-based framework designed to empower LLMs to autonomously invoke multiple external tools during stepwise reasoning. Tool-Star integrates six types of tools and incorporates systematic designs in both data synthesis and training. To address the scarcity of tool-use data, we propose a general tool-integrated reasoning data synthesis pipeline, which combines tool-integrated prompting with hint-based sampling to automatically and scalably generate tool-use trajectories. A subsequent quality normalization and difficulty-aware classification process filters out low-quality samples and organizes the dataset from easy to hard. Furthermore, we propose a two-stage training framework to enhance multi-tool collaborative reasoning by: (1) cold-start fine-tuning, which guides LLMs to explore reasoning patterns via tool-invocation feedback; and (2) a multi-tool self-critic RL algorithm with hierarchical reward design, which reinforces reward understanding and promotes effective tool collaboration. Experimental analyses on over 10 challenging reasoning benchmarks highlight the effectiveness and efficiency of Tool-Star. The code is available at https://github.com/dongguanting/Tool-Star.