CoGrid & the Multi-User Gymnasium: A framework for multi-agent experimentation

Abstract The increasing integration of artificial intelligence (AI) in everyday life brings with it new challenges and questions regarding how humans interact with autonomous agents. Multi-agent experiments, where humans and AI act together, can offer important opportunities to study social decision-making, but there is a lack of accessible tooling available to researchers to run such experiments. We introduce two tools designed to reduce these barriers. The first, CoGrid , is a multi-agent grid-based simulation library with dual NumPy and JAX backends. The second, Multi-User Gymnasium ( MUG ), translates such simulation environments directly into interactive web-based experiments. MUG supports interactions with arbitrary numbers of humans and AI, utilizing either server-authoritative or peer-to-peer networking with rollback netcode to account for latency. Together, these tools can enable researchers to deploy studies of human–AI interaction, facilitating inquiry into core questions of psychology, cognition, and decision-making, and their relationship to human–AI interaction. Both tools are open source and available to the broader research community. Documentation and source code is available at {}. This paper details the functionality of these tools and presents several case studies to illustrate their utility in human–AI multi-agent experimentation.