Workshop and whiteboard pages, and read_page_data, removed from the Artifact tool

What

The Artifact tool publishes pages that Claude creates. Its workshop-page features, and several related ones, are gone from this build.

• read_page_data is removed. It was an action that checked a page's data against a schema. validateInput now only routes verify, and read_page_data is no longer on the read-only action list or a tool-name list. The session fields artifactReadPageDataApproved and artifactReadPageDataHumanApproved and the recordedPages checks are gone with it. Other actions (verify, upload_asset, read_file, read, delete) remain.
• Publishing no longer offers a template choice (workshop, whiteboard, heli, prototype). The template is always "plain", and verifyWorkshopHtml, the workshop HTML structure check, no longer runs.
• The workshop sidecar checks are gone, including the refusal to copy renderable or executable side files on workshop pages. File copies go straight to the document, SVG and script checks.
• The retry for too many block IDs and the injection of doc block IDs are gone.
• workshop_schema and workshop_ambiguous are no longer handled in publish-conflict messages.
• isWorkshopWrite, workshopDocPath, authoringProgress, authoringProgressSurface, frozenReadPageDataSchemaNames, lastSnapshottedWorkshopDoc and includeWorkshopDoc are gone.
• The prompt text telling Claude to load the skill before writing the file was replaced with an empty helper.
• page_data is no longer accepted as a kind in one parser.
• Workshop, whiteboard (whiteboard_publish, whiteboard_turn) and heli (heli_publish, heli_started, heli_turn) tracking was removed, along with the workshop write counts.
• ownPublishedSlugs entries gain byPerson when the read is by the owner and the conversation passes a check.
• "mantle" was removed from a provider list.

The same findings note two unrelated additions: date announcements gain an assumed_utc field, and an input_send_now_click name was added.

Why

If you relied on workshop or whiteboard pages, or on read_page_data to check page data, those are no longer available. Artifacts now publish as plain pages.