Anthropic switched to HTML artifacts from Markdown to speed up internal work...

https://romeo-wiki.win/index.php/How_do_I_turn_one_HTML_template_into_100_different_reports_with_JSON_swaps%3F

Anthropic switched to HTML artifacts from Markdown to speed up internal work like planning, code reviews, and reports. HTML cuts output costs to just $0.08 per file and loads content 5x faster, which boosts productivity