handback

The mailbox reply flow with the recipient fixed to your parent — the from of your message-zero, the bootstrap handoff you drained on launch.

1. Find your message-zero — the message whose subject begins spawn:, in your archive/ (or inbox/ if still unread):

   zero="$(grep -rlE '^subject: spawn:' "$(mb_dir "$(mb_resolve_self)")"/{archive,inbox} 2>/dev/null | head -1)"
   

2. Run the mailbox reply flow against $zero — compose the return body per the mailbox compose rules and stream it in. It sends home, threaded to your parent. Confirm to the operator what was sent and to whom (mb_whois for the parent's friendly name).

If there is no spawn: message-zero you were not created with a return channel, so there is no parent — use dispatch to send to a named peer instead.