RL Environments at Scale – Will Brown, Prime Intellect
Dec 9, 2025 · 18:30
Will Brown of Prime Intellect argues that scaling reinforcement learning environments beyond engineering—to community and accessibility—is key to broadening AI research. He presents Prime Intellect's open-source stack, including Verifiers for building environments and the Environments Hub for sharing them, as a way to turn any task harness into an RL training or evaluation loop. Brown demonstrates how environment-based fine-tuning boosted a Qwen 3 4B model from 55% to 89% on a Wikipedia search task, matching much larger models. He frames environments as the 'web apps of AI research'—simple to start, but capable of capturing product complexity, as seen with Cursor's Composer and OpenAI's Codex. Prime Intellect validated this approach by training the 100B-param Intellect 3 on 500 GPUs, and will soon release Lab, a platform to run environments without managing infrastructure.
