What
Claude can now upload CSV, Markdown, JSON and plain text files into an artifact's asset store, not just images, video, PDFs and fonts. The instructions also tell Claude to reference an uploaded file by the url returned in the result exactly as given, replacing the older relative _blob/{id} form.
Details
- Only artifacts whose page declares the
assetscapability accept uploads. - This text appears only when the artifact asset-store section of the tool prompt is emitted, which is decided by the tool's own capability check rather than a named setting.
Evidence
text file (CSV, Markdown, JSON, plain text) into an existing artifact whose page declares the assets capability
Strings lifted out of the shipped bundle, so the claim above can be checked against them.