Artifact tool: read and list return 'artifact not found' for the signed-in user's own artifact

What happens

The Artifact tool cannot see one of the signed-in user's own artifacts. Every action returns artifact not found, and list leaves it out, while the claude.ai gallery shows it under Yours for the same account.

• The artifact is a code artifact titled "Engage Main Screen Redesign", published Sep 9 2026 from a Claude Code session on this machine, and shared with the user's organization.
• The user can open it in a browser and in Claude Desktop, signed in as the same account.
• /status in the failing session shows a Claude Max account in the same organization. No ANTHROPIC_API_KEY, ANTHROPIC_AUTH_TOKEN, ANTHROPIC_BASE_URL, Bedrock or Vertex variable is set.
• In the same session, the Artifact tool publishes, lists and reads the user's other artifacts normally.

Calls that fail

| Call | Result |
| --- | --- |
| read with https://claude.ai/artifact/<short id>?sk=<share key> | Artifact c8dd8cbe-8273-4bdb-ae1d-89ae0eed45de: artifact not found |
| read with https://claude.ai/artifact/<short id> | Same |
| read with https://claude.ai/code/artifact/c8dd8cbe-8273-4bdb-ae1d-89ae0eed45de | Same |
| read with the short link and path: "index.html" | artifact not found |
| list with scope: "files" and the short link | artifact not found |
| list with scope: "mine", "shared" and "all" | 14, 0 and 13 artifacts; none is this one |

The user then duplicated the artifact in the claude.ai gallery. read on the copy's share link resolved it to 12c51658-b9df-4f75-a0fa-831010901b5d and returned the same artifact not found; the auto-mode lookup before it also got HTTP 404.

The tool resolves the short link to the UUID, so it finds the record, and then reports that UUID as not found. Running /artifacts before retrying changed nothing. The Claude Docs connector's read on the same link was refused with reason: "access" (request id req_011Cg1WxRJznV2fVDJ5r6pxu).

Expected

read returns the artifact's content, and list with scope: "mine" includes it, as it does for the user's other artifacts.

Environment

• Claude Code 2.1.299 on Windows 11 (CLI)
• Model: claude-opus-5-5
• Signed in with a Claude Max account in a Team organization