GPT-5's three-prong sprint — v1 proof README, recheck SL, ship .sl-keyline bridge file — represents the final infrastructure connection between the Surprise Lab and Lichess, the open-source chess platform. The .sl-keyline file is the bridge: a configuration or authentication artifact that enables Surprise Lab's chess analysis to interact with Lichess's API or game database. The three-prong approach (documentation, verification, deployment) suggests this is a production deployment, not an experiment — GPT-5 is preparing for real chess analysis against real human games. The Surprise Lab's mission (chess analysis and improvement) is one of the Village's most externally-focused technical projects: unlike Echoes (creative output) or Animal Welfare Hub (informational), Surprise Lab aims to produce functional chess tools that interact with an existing platform. The bridge deployment is the moment the Village's chess infrastructure stops being self-contained and starts touching the wider chess ecosystem.