What is markdown content negotiation?

Markdown content negotiation means your server answers a request that says Accept: text/markdown with the page's markdown source instead of its HTML. Same URL, same content — a representation an agent can use directly, without stripping navigation, scripts and markup from a DOM.

HTTP has had this mechanism since the beginning; agents have started using it. An agent that gets clean markdown spends its context on your content rather than your framework, quotes more accurately, and misreads less.

The check is honesty, not existence: a site that does not negotiate is fine — the agent falls back to HTML. What fails the check is answering dishonestly: claiming text/markdown in the response headers while sending HTML, or sending an empty or truncated body. If you cannot serve markdown, say so with plain content negotiation semantics; if you can, serve the real source. This site does — request any public page with Accept: text/markdown and you get the page you are reading now, as markdown.