You'll notice
Publishing an artifact now requires saving it to an .html file and supplying file_path plus a one-or-two-emoji favicon
What
The publish action for artifacts (self-contained pages Claude can build, like a small web app) no longer accepts the page content directly as a parameter. Instead:
- Claude must write the page to an
.htmlfile first - The publish call must then pass
file_pathpointing to that file - The publish call must also pass a
favicon, made of one or two emoji - A variant of the flow also supports starting from a
type_url
Why
This changes how artifacts get published: rather than sending content inline in one step, Claude writes a file and references it, and every published page now gets an emoji favicon. This mainly affects the internal mechanics of publishing, but it means a published page always has a favicon set.