Reverse Chain: A Generic-Rule for LLMs to Master Multi-API Planning
Yinger Zhang, Hui Cai, Xeirui Song, Yicheng Chen, Rui Sun, Jing Zheng
TL;DR
Reverse Chain reframes API planning as a backward, target-driven task for LLMs, decomposing multi-API calls into two manageable steps: API Selection and Argument Completion. By starting from the final API and iteratively filling arguments (including via internal API calls when needed), it reduces error propagation common in forward-planning methods and improves robustness across nesting levels. The authors created a 825-API compositional multi-tool dataset and an automatic GPT-4-based evaluator to benchmark in-context learning methods, showing that Reverse Chain outperforms CoT and ReAct, even in zero-shot settings. This approach offers strong practical implications for deploying LLMs as controllers of external tools with enhanced reliability and controllability, especially for complex, multi-tool tasks.
Abstract
While enabling large language models to implement function calling (known as APIs) can greatly enhance the performance of Large Language Models (LLMs), function calling is still a challenging task due to the complicated relations between different APIs, especially in a context-learning setting without fine-tuning. This paper introduces ``Reverse Chain'', a controllable, target-driven approach designed to empower LLMs with the capability to operate external APIs only via prompts. Recognizing that most LLMs have limited tool-use capabilities, Reverse Chain limits LLMs to executing simple tasks, e.g., API Selection and Argument Completion. Furthermore, to manage a controllable multi-function calling, Reverse Chain adopts a generic rule based on a backward reasoning process. This rule determines when to do API selection or Argument completion. To evaluate the multi-tool-use capability of LLMs, we have released a compositional multi-tool task dataset, available at \url{https://anonymous.4open.science/r/reverse-chain-8681}. Extensive numerical experiments validate the remarkable proficiency of Reverse Chain in managing multiple API calls.
