Scaling Environments for Agents

This book constitutes the refereed proceedings of the First International Workshop, SEA 2025, Held in Conjunction with NeurIPS 2025, in San Diego, CA, USA, during December 7, 2025.The 20 full papers presented in this book were carefully selected and reviewed from 154 submissions. They focuses on benchmarks and evaluation; learning and fine-tuning through interaction; tool-use and software environments; multi-agent systems and simulation; embodiment and grounding; and sim-to-real deployment.