AcceptMarkdown.com promotes serving Markdown versions of web pages to AI agents through HTTP content negotiation. Clients can request a Markdown representation with the `Accept: text/markdown` header, allowing them to receive page content without navigation, scripts, styles, layout wrappers, advertisements, related-content sections, or modal overlays. The site says Markdown responses use a fraction of the bytes of full pages and can leave AI agents’ context windows focused on prose rather than DOM markup. It also says cleaner text can improve signal-to-noise for retrieval-augmented generation pipelines and that smaller responses can reduce fetching, parsing, and context-loading work before a model begins generating output. Its URL checker sends an edge request with `Accept: text/markdown` and reports what the origin returns. The checker evaluates whether a URL serves Markdown for that request, sets `Vary: Accept`, rejects unsupported content types with HTTP 406, and honors HTTP `q` quality values in Accept headers.