What
Guidance on artifact comment threads changed. A thread is activated by replying with Send to Claude or by mentioning @claude, and when Claude cannot resolve a thread that was never activated it must leave it open and tell you that a writer can send it to Claude or resolve it in the artifact view. The old wording just told Claude to leave the thread for the commenter.
Evidence
reply on it with Send to Claude
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Names in the bundle@claude
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up @claude, on All settings.
* **Type**: array of objects, each with `marketplace` and `plugin` strings. An entry can instead be a `"plugin@marketplace"` string such as `"telegram@claude-plugins-official"`, which Claude Code treats as the equivalent object. The string…settings-reference see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up @claude, on All settings.