You'll notice
If the session has no tool that can read or reply to artifact comments, you are now told once and asked to reply on the page.
Artifact-comments auto-reply now detects when the current session has no MCP tool capable of reading or replying to artifact comments, and surfaces a one-time notice under a new reply_tool_absent case: "this session has no tool that can read or reply to artifact comments." Previously this failed silently or posted nothing without explanation; now the user is told to answer on the page themselves.