Shopify's River Agent: 5,938 Employees, 1,870 PRs per Week, 1 in 8 Merged PRs Now AI-Authored

Simon Willison·medium signal

Simon Willison highlights Shopify's internal River agent, which operates entirely in public Slack channels — it refuses DMs and suggests public channels instead. In the last 30 days, 5,938 Shopify employees used River across 4,450 channels, with the agent opening 1,870 pull requests in one week in the main monorepo. Roughly one in eight merged PRs is now River-authored and human-reviewed. Shopify CEO Lütke's own River channel has 100+ colleagues who react and add context, creating what Willison calls a 'Lehrwerkstatt at scale' — osmosis learning without formal training.