Claude is now told to read claude.ai artifact links with the Artifact tool or WebFetch, never curl or a headless browser
Claude Code's instructions now explain that claude.ai artifact links — of the form claude.ai/artifact/{id} or claude.ai/code/artifact/{uuid}, including on preview.claude.ai — are published artifacts and should be read using the Artifact tool's "read" action, or via WebFetch using the user's claude.ai login. The instructions explicitly warn against fetching such links with curl or a headless browser, which return either the app's empty page shell or a Cloudflare 403 error.
This steers Claude toward methods that can actually retrieve artifact content and away from methods that reliably fail on these links, avoiding wasted attempts and confusing error pages.