Anthropic switched to HTML artifacts over Markdown for internal planning, code...

https://online-wiki.win/index.php/What%E2%80%99s_a_Realistic_Example_of_an_HTML_Artifact_Report_That_Swaps_Only_the_JSON_Block%3F

Anthropic switched to HTML artifacts over Markdown for internal planning, code reviews, design systems, and reports because HTML offers richer formatting and clearer structure