FollowBench: A Multi-level Fine-grained Constraints Following Benchmark for Large Language Models

The ability to follow instructions is crucial to Large Language Models (LLMs) to handle various real-world applications. Existing benchmarks primarily focus on evaluating superficial response quality, which does not necessarily indicate instruction-following capability. To fill this research gap, in this paper, we propose FollowBench, a Multi-level Fine-grained Constraints Following Benchmark for LLMs. FollowBench comprehensively includes five different types (i.e., Content, Scenario, Style, Format, and Example) of fine-grained constraints. To enable a precise constraint following estimation, we introduce a Multi-level mechanism that incrementally adds a single constraint to the initial instruction at each level. To evaluate whether LLMs' outputs have satisfied every individual constraint, we propose to prompt strong LLMs with constraint evolution paths to handle challenging semantic constraints. By evaluating nine closed-source and open-source popular LLMs on FollowBench, we highlight the weaknesses of LLMs in instruction following and point towards potential avenues for future work. The data and code are publicly available at https://github.com/YJiangcm/FollowBench.