Changes to how Claude Code automatically responds to artifact comments

What

Artifact comments are comment threads left on artifacts, the pages Claude Code produces. The auto-react flow is the part of Claude Code that notices those comments and responds to them automatically. Several parts of this flow changed.

• A path for pages driven through MCP hands a comment thread directly to the session, meaning your ongoing conversation with Claude Code. MCP (Model Context Protocol) is the standard Claude Code uses to talk to outside tools and services. This path runs only after the checks on usage limits and plan mode have passed, and before the usual reply-tool path.
• The MCP hand-off path can decline to hand over a thread. Its reasons include no_send, thread_not_listed, reply_denied and nobody_to_ask.
• The scan for comments no longer stops early when an initial check is met. Before, it began with if (wu()) return;.
• When a rule is withheld, the flow now also sends a notification that includes the current state.

Why

In practice, the scan now continues in a case where it used to stop. A withheld rule now produces a notification instead of passing silently. Comment threads on MCP-driven pages can go straight into the session. Together, these changes may affect when, and whether, artifact comments get an automatic response.