What
An artifact is a self-contained page or small app that Claude builds for you. The instructions Claude follows when building one now say this about the hash, the part of a link after #:
- Only a plain
#namepasses from the artifact's link to the page. - The page should react to the hash changing to decide what to show.
- Names should use ASCII letters, digits and hyphens only. The earlier guidance also allowed
.,_and~. - Keys, tokens and private values must stay out of the hash, because it shows in browser history and in copied links.
- Names starting with
comment-are reserved.
Why
This changes how artifacts Claude builds handle deep links, meaning links that open straight to one part of the page. Links into artifacts should be simpler and should not leak private values when shared.