Vyasa is a live document server that keeps three concerns loosely coupled: request routing, Markdown-to-HTML rendering, and page shell composition. A request enters through the CLI-booted app in vyasa/main.py, routes through handlers in vyasa/content_routes.py, and is finally wrapped by render_layout(). This guide is for understanding that flow well enough to debug or extend it. The useful mental model is "one content tree, many render modes, one shared shell."