Abstract:This paper presents the novel method StreamLLM for generating streamliners in constraint programming using Large Language Models (LLMs). Streamliners are constraints that narrow the search space, enhancing the speed and feasibility of solving complex problems. Traditionally, streamliners were crafted manually or generated through systematically combined atomic constraints with high-effort offline testing. Our approach uses LLMs to propose effective streamliners. Our system StreamLLM generates streamlines for problems specified in the MiniZinc constraint programming language and integrates feedback to the LLM with quick empirical tests. Our rigorous empirical evaluation involving ten problems with several hundreds of test instances shows robust results that are highly encouraging, showcasing the transforming power of LLMs in the domain of constraint programming.