At Anthropic, we switched from Markdown to HTML artifacts for internal...

https://spark-wiki.win/index.php/What_is_the_Claude_Side_Panel_Live_Preview_for_Artifacts_and_Why_Does_It_Matter%3F

At Anthropic, we switched from Markdown to HTML artifacts for internal planning, code reviews, design systems, and reports because HTML cuts output costs by 8 cents per item and loads 5 times faster