Abmarl is a package for developing Agent-Based Simulations and training them with MultiAgent Reinforcement Learning (MARL). It provides an intuitive CLI for engaging with the full workflow of MARL experimentation: training, visualizing, and analyzing agent behavior. Abmarl leverages RLlib’s framework for reinforcement learning and extends it to more easily support custom simulations, algorithms, and policies. Abmarl documentation is also available.