Game source and proof
Project: project.godot; scene: scenes/Main.tscn; starter mechanics: scripts/main.gd. Lumen draws its own art and supports keyboard and pointer/touch destinations.
sh "$GODOT_SKILLS/godot/scripts/export-web.sh"
The helper copies source (excluding build/cache directories), imports, runs scripts/proof.gd, then exports the Web preset into fresh staging. GODOT_BIN selects an editor, and GODOT_WEB_TEMPLATE an optional matching single-threaded release template. Node 20+ bootstraps through the package helper.
Proof must instantiate real gameplay and assert meaningful state transitions. On success it writes {"passed":true,"checks":[...]} to HARNESS_BUILD_DIR/proof.json; on failure exit nonzero. A missing receipt is failure even if Godot exits zero. Keep assertions relevant when replacing the starter. A standalone proof can write to Godot's user data directory when that environment variable is unset.
Use _physics_process for movement and keep per-frame work bounded. Preserve keyboard, touch/click, pause and restart when useful for the requested game. The custom web/shell.html exposes actual game state through JavaScriptBridge, not a parallel simulated game.
The build verdict means native assertions and export passed. Verify the exported game in the actual shared viewer before claiming browser readiness. A browser playthrough must exercise game results, not just see a canvas.
The viewer requires a single-threaded export (Godot 4.3+), Compatibility renderer, no service worker or persistent browser storage. Keep the editor and templates version-matched. Only Godot 4.4's known optional PWA callback warning is downgraded in the opaque sandbox; other engine errors remain visible.
Optional interaction/performance probe:
HARNESS_WORKSPACE="$PWD" node "$GODOT_SKILLS/godot/scripts/perf.mjs" build/web/index.html
Uses shared Web Viewer + Playwright and the assertions in proof.json. It reports actual interaction frame timing; inspect the recorded renderer and do not extrapolate hardware performance to other devices.