In messages.visibleReplies "message_tool" sessions, a successful agent turn that produced a substantive private final without calling message(action=send) previously left the user with silence and only an operator log. The gateway now enqueues one protected front-of-queue retry prompting the model to deliver the reply, and falls back to a sanitized visible diagnostic when the retry cannot be enqueued or also strands. Queue overflow protection is unified with the in-flight-aware drop policy (skip in-flight or protected items, reject when nothing is droppable), rejected overflow no longer refreshes the drain debounce, heartbeat turns are excluded from recovery, and recovery retries no longer share the client turn's queued-turn lifecycle.
Fixes#85714
Thanks to Eva (@100yenadmin) for the contribution.
ae63a48e94
