What
The Artifact tool now wraps content in a <!doctype html>…<head>…</head><body> skeleton automatically at publish time, so content files should be written without those outer tags.
Details
- Write the page content directly (body content, CSS, scripts) — no
<!DOCTYPE>,<html>,<head>, or<body>tags of your own - Unless the user specifies a location, the recommended place for artifact files is the scratchpad directory listed in the system prompt
- All other existing rules (self-contained, no external resources, responsive, favicon) are unchanged
Evidence
Updated Artifact tool description (search for "wrapped in a", "<!doctype html>", "write the page content directly")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.