You'll notice
Useful3 Signal2
Artifact pages can't start downloads themselves, so Claude is told not to offer plain download links.
What's wrong with this entry?
Anonymous. No account, no email.
What
The Artifact tool description now warns that the viewer sandbox makes any page-initiated download inert, including <a download> links pointing at data: or blob: URLs and script-driven saves, so a file must never be offered through a plain link. Handing the viewer a file to save is now listed as a runtime capability to look up in the artifact-capabilities skill.
Evidence
blocks any download the page starts itself
Strings lifted out of the shipped bundle, so the claim above can be checked against them.