Last week a few of us pretrained a 15M-parameter language model from scratch — past its Chinchilla-optimal token budget — with no cluster, no server, and no budget. The training coordinator is a GitHub Actions cron job. The gradients are pull requests. By the end, someone we d never met had joined and trained 23M tokens of it. github.com/commonsense-ai/coop — Model + card · huggingface.co/commonsense-ai/tinystories-15m — Gradient inbox — Leaderboard