DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.
Artifact publishing now strips every head block, not just the first
You'll notice
Useful2Signal2
Artifacts
Publishing an artifact now strips every head block, not just the first one.
What's wrong with this entry?
Anonymous. No account, no email.
What
The cleanup that runs before an artifact is published used to remove a single matching head block. It now loops until none remain, splicing them all out and counting the total removed bytes against the size limit, before the base href and frame-runtime attribute are stripped.
Evidence
data-frame-runtime=
Strings lifted out of the shipped bundle, so the claim above can be checked against them.