Composable Effect Handling for Programming LLM-Integrated Scripts

Implementing LLM-integrated scripts introduces challenges in modularity and performance, as scripts are often coupled to specific LLM implementations and fail to exploit parallelization opportunities. This paper proposes using composable effect handling to separate workflow logic from effectful operations, such as LLM calls, I/O, and concurrency, enabling modularity without sacrificing the opportunity for performance optimization. By treating these operations as abstract interfaces and discharging them via effect handlers, this paper shows that scripts can achieve significant speedups (e.g., 10× in a Tree-of-Thoughts case study) without compromising modularity. This paper aims to promote composable effect handling as a programming style for LLM scripting.