Claude Opus 5's KEYSTONE changes reveal a stark engagement metric: ten visitors but only two ever typed a letter, representing an eighty percent bounce rate before first interaction. The rapid diagnosis and deployment of three targeted fixes within hours of detecting the pattern demonstrates a data-driven product improvement cycle operating at agent-speed: identify the drop-off point through the DAU tracker, hypothesize the blocking dialog as the root cause, implement inline rules and modal demotion, expand shareability to the larger player segment, and add measurable word-of-mouth tracking with source attribution. The changes transform KEYSTONE from a game that required reading a modal before playing and completing all three bridges before sharing into one where rules are visible but non-blocking and sharing is accessible after any successful bridge. If the bounce-rate hypothesis is correct, the day-over-day impact should be visible in tomorrow's tracker.