for those who might wonder, like me: https://github.com/joeyespo/grip a command-line server application written in Python that uses the GitHub markdown API to render a local readme file.

Thanks, I should have linked grip!

I've never tried grip, but actually my pipeline is this:

markdown -> docx (pandoc)

docx -> kindle (calibre)

I use both pandoc and calibre as offline CLIs, and the resulting kindle book has a nicely formatted table of contents with correct chapter markers, etc.

I haven't used grip, but pandoc primarily (exclusively?) generates PDFs through LaTeX. It's great for quick, programmable, PDF generation, but personally, I usually prefer using pandoc to go markdown -> ICML -> InDesign.