html-over-markdown
Generate rich, self-contained HTML documents instead of Markdown when output needs visual hierarchy, diagrams, or interactivity. Use for specs, implementation plans, side-by-side design comparisons, PR writeups and code explainers, research and status and incident reports, slide decks, SVG flowcharts, and throwaway editors like triage boards, feature-flag editors, and prompt tuners. Prefer this skill whenever the user asks for a report, plan, or explainer they'll actually want to read — even if they don't explicitly say "HTML".