What
When you publish an artifact (a shareable page Claude Code builds, such as a small app or interactive doc), Claude Code now checks whether the artifact still literally mentions the name of an MCP server (an external tool source) that was renamed as part of publishing. If the page's own text or code still refers to the old name as a quoted string, you now get a warning that any calls using that old name will fail for every viewer, and that you should use the display name instead.
Why
Before this check, an artifact could silently reference a server name that no longer exists after publishing, breaking it for anyone who opens it. The new warning catches this at publish time instead of leaving viewers to hit a mysterious failure later.