Premise 1: Humans hand-edit content. Markdown was designed for people who write and revise their own text. That’s how blogs, docs, and READMEs still work. But agent output is different. You send a prompt. The agent generates a 2,000-word analysis, a code review, a project plan. You read it, maybe share it. You almost never open it in an editor and start rewriting paragraphs. The format’s core value proposition — easy to edit by hand — no longer matches the use case.