Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
ArtifactsArea: what it touches
Internal ChangesKind: in v2.1.321,
Internal ChangesSection of the release
What
When Claude uses a tool, Claude Code sends a description of that tool use to connected apps so they can display it. That description has a new optional true-or-false field, artifact_publish.
It is set to true when Claude calls a publishing tool on an Artifacts MCP server (MCP is the standard way Claude Code connects to outside tools) that talks only to Anthropic's own server. It is sent only for the main conversation, not for helper agents running underneath it.
Why
Apps built with the SDK and remote clients can now show clearly when Claude has published an artifact.
