mhr shows a markdown file in a native window and re-renders it every time the file changes on disk. Your scroll position stays where it was. There is no editing surface, and mhr never writes to the file it opens.

It is built for reading files you did not write, such as a plan produced by an AI agent or a README from a repository you just cloned:

• No network access. The window blocks every outgoing request, so a document renders the same way with the network disconnected.
• No server and no port. Most markdown previewers render to a localhost page that any other process on the machine can read. mhr opens a window instead.
• Raw HTML is filtered to the same safe subset GitHub allows. Hand-written tables, <details> and <kbd> render; <script>, <style>, event handlers, inline styles and non-web URLs are removed.

It renders GitHub Flavored Markdown, including tables, task lists, footnotes and alerts, plus syntax-highlighted code blocks, math converted to MathML and Mermaid diagrams. Front matter is removed cleanly instead of showing as a stray paragraph. Images do not display, because mhr reads only the single file you name.

• Open a file from a terminal with: mhr notes.md
• Or right-click a markdown file in your file manager and choose mhr from the "Open With" menu.