Type a question in plain English or Spanish (“cooling centers in Flushing”, “Penn Station to Grand Central, wheelchair”). A 1B-parameter Granite 4.0 model running on WebGPU picks one of three routing tools and dispatches it against locally-loaded OSM walk graphs and MTA accessibility data. The router is compiled to WASM from Rust (Dijkstra over petgraph + rstar). Wheelchair queries filter to ADA-accessible stations with elevators-out-today removed (the only network call after assets load). Model, router, geocoder: all in-browser. After the initial asset download you can go offline and the app still produces routes.