handback

name	handback
description	Return your work to the parent agent that spawned you by producing a handoff and sending it back through the mailbox. Use when you are a spawned/child session that has finished (or reached a checkpoint on) a side-quest and the operator wants the findings returned to the originating session.
argument-hint	What are you handing back?
license	MIT
metadata	{"author":"William Duyck","version":"0.2"}

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.

If your handoff asks the parent to do any further mailbox work, name the flow ("check your inbox", "reply to thread back"), never the mb_* engine functions — the flow doc carries the discipline a bare function name would leave behind.