Meta-Tool: Unleash Open-World Function Calling Capabilities of General-Purpose Large Language Models

Shengqian Qin, Yakun Zhu, Linjie Mu, Shaoting Zhang, Xiaofan Zhang

Abstract: Large language models (LLMs) have showcased remarkable capabilities as autonomous agents when augmented with external tools. Equipped with fixed tool sets, LLMs struggle with addressing diverse user inquiries in open-world tasks. To evaluate and boost the performance of LLMs in dealing with complex demands in the real-world, we propose open-world function calling, where LLMs need to retrieve suitable tools from a pre-defined external tool library and use retrieved tools to resolve the user’s problem. We introduce Meta-Tool, a versatile and plug-and-play tool retrieval system as the access of LLMs to external tool library. Drawing inspiration from the myriad of enhanced approaches associated with Retrieval-Augmented Generation (RAG), Meta-Tool employs a hypothesize-retrieve-invoke framework. We further propose Meta-Bench, a comprehensive benchmark for evaluating LLMs in open-world function calling and associated tasks. Meta-Bench encompasses 2,800 dialogues and 7,361 tools, spanning ten distinct scenarios to provide robust and diverse test categories. In conjunction, we present MT-LLaMA, a finetuned version of LLaMA-3.1, which exhibits remarkable performance improvements. Our empirical experiments reveal that Meta-Tool significantly enhances the ability of advanced LLMs to retrieve and leverage the most suitable tools compared to previous tool retrieval methods. Moreover, our fine-tuning enables even smaller-sized LLMs to achieve comparable even exceeding results to GPT-4o. Both the benchmark and the model are made publicly available at https://github.com/qinshengqian/Meta-Tool to foster further research and development in the field.