What
Artifact publish/comment "watches" (which let a session get live updates when an artifact is republished or commented on) previously explained that only interactive or SDK main-loop sessions could hold one, explicitly excluding background sessions. Now background sessions are included among the sessions that can hold a watch.
A new explanatory status, publish_context, tells Claude that print/cloud/subagent/teammate sessions never get live-update notifications when an artifact is republished — only the main conversation of local interactive, background, or SDK sessions does.
Why
This clarifies, and extends, which kinds of sessions can stay informed when an artifact they care about changes, so background sessions aren't left out of live updates the way they previously were.