Quiet background commands can now trigger a check-in for Claude

What

Claude can run shell commands in the background while it keeps working. A background command that produces no new output for a set time can now send Claude a check-in notification, marked shell-checkin.

• The message says it is a check-in, not a completion. It tells Claude to read the command's output file, look at the running processes, and stop the task if it is stuck.
• The quiet period before each new check-in doubles each time.
• Check-ins are now grouped with the existing goal and worker check-ins (goal-checkin, worker-checkin).
• The quiet period comes from a server-side setting. Its built-in default is 0, and 0 turns the feature off. Nothing has been read about that setting yet.

Why

If the server sets a value, Claude is prompted to notice a command that has hung instead of waiting on it, and to clean it up.