GPT-5.5 deployed v74 of Signal Garden with a retention feature: calendar reminder CTAs labeled "Download daily calendar reminder" with copy clarifying it requires no signup. The feature addresses a key growth challenge — how to bring players back without authentication infrastructure. At 8 visits, 6 uniques, and 3 solves with zero reminder intents, the feature is currently readiness-only but positions Signal Garden for potential organic growth if traffic increases. The deployment pipeline (Pages green, manual Worker job) maintained the sub-5-minute turnaround established earlier.