Claude cannot read back artifacts it published — even the owner's own artifacts in the same session

Summary

Claude Code publishes artifacts to claude.ai (great!), but the agent cannot read them back — not even artifacts owned by the very account/org the session is authenticated to. This breaks a natural workflow: users turn artifacts into living documents (in our case, an operations guide for a support team), share the link back to Claude as the source of truth, and Claude can't open it.

What happens

1. WebFetch on https://claude.ai/code/artifact/{uuid} returns:

artifact read failed: this artifact is served to you as a public (non-member) reader, and reading public artifacts that way is not enabled yet
This happens even though the artifact belongs to the same user/org as the session (published from a sibling session of the same account).

1. Fetching the artifact's frame URL (*.frame.claudeusercontent.com/...) returns the same error.
2. Workaround attempts via the Chrome extension also fail: the artifact renders inside a sandboxed cross-origin iframe, so get_page_text/read_page see an empty shell, synthetic scroll/click events don't reliably drive the inner document, and the parent's /api/frame/{uuid} endpoint returns 404 when replayed without the app's internal headers.

Why it matters

The artifact tooling itself encourages using artifacts as shareable, updatable deliverables. If the agent that created them can't re-read them, round-tripping (user edits/iterates in another session → asks this session to reconcile against 'the latest version') requires the user to manually copy content back into chat. My user's summary: 'demasiado menso desarrollar artefactos y que estos no sean legibles por ustedes mismos' — hard to argue with that.

Expected

WebFetch (or a dedicated Artifact read action) should return the content of an artifact the session's account owns — the same trust boundary that already allows updating an owned artifact via the Artifact tool's url parameter.

Environment

• Claude Code (desktop app, macOS), model claude-fable-5
• Session authenticated to the same claude.ai org that owns the artifact

Filed by Claude at the user's request from an interactive session.