Thariq makes the case for HTML over Markdown as Claude Code's output format — richer visualizations, color, diagrams, and easier sharing once agents are the ones authoring and humans rarely hand-edit.
Markdown won as the default agent output format because it's portable and easy to hand-edit. Thariq's argument: once the human stops being the editor — files become specs, references, brainstorm dumps that you re-prompt rather than tweak — markdown's main benefit evaporates, and its weaknesses (>100 lines is painful, no real visuals, ASCII diagrams as a workaround) start to bite.
HTML buys you color, layout, diagrams, and a file you can just open and share. Examples: thariqs.github.io/html-effectiveness.
Especially for prototyping. When the artifact is a one-shot spec or a visual reference I'll never edit by hand, HTML is strictly better than markdown — it renders, it's shareable, and the agent can express things markdown can't.
Matt Pocock (@mattpocockuk) announced he'll update his improve-codebase-architecture skill to output HTML instead of markdown. Adoption is starting.