What problem does it solve? Large self-contained HTML apps (desktop-OS shells, multi-app dashboards, 5000+ lines) exceed the ~8K token limit of a single write_file call, causing silent stream-timeout failures. This Skill provides a proven scaffold-and-patch technique to build, verify, and debug such files reliably. ## Core Features & Use Cases - Slot-and-patch build technique: Scaffold a skeleton HTML file with unique slot markers, then fill each slot with small patch calls that stay under the stream timeout, with recovery steps for stalled calls. - Architecture patterns: App registry plus window manager for multi-app shells, localStorage state persistence, and CSS custom-property theme systems. - Two-layer verification: Extract inline script and run node --check for exact syntax-error line numbers, then serve over HTTP and exercise every feature via Playwright DOM evaluation. - Use Case: Build a Windows-style desktop OS in one HTML file with 14 working apps, an animated wallpaper, and a notification center — delivered as a ~110KB single file across staged, verified patches. ## Quick Start Use the single-file-html-app skill to build a desktop OS shell with multiple working apps as one self-contained HTML file.
