Fly Proxy autostop judges idle exclusively on inbound proxied connections.
It cannot see an in-flight agent turn (outbound-only LLM traffic), and since
Fly's mid-2026 proxy change an open outbound socket (the relay WS) no longer
holds a machine awake. With autostop:"suspend", Fly suspended machines while
they were still processing long-running jobs, and could suspend before the
gateway flipped the relay destination (the buffered-event black hole).
The scale-to-zero watcher now owns the suspend: after the idle predicate
holds (no running agents, no live background work, inbound-quiet) and the
go_dormant() quiesce completes (relay drained + flipped), it POSTs
/v1/apps/{app}/machines/{id}/suspend on the local /.fly/api flaps socket.
Suspend is skipped when the quiesce fails or inbound lands mid-quiesce
(flip-before-freeze), and off-Fly the step is a no-op (fail-awake).
Pairs with the NAS change that provisions scale-to-zero machines with
autostop:"off" (gateway-owned suspend); wake is unchanged (Fly-proxied
wakeUrl poke + autostart).
The gateway-side BEHAVIOUR layer that consumes the relay scale-to-zero
primitives (gateway-gateway Phase 5): the gateway decides it is idle and
drives the relay transport dormant so the platform (Fly autostop:"suspend")
can suspend the now-traffic-idle machine, which wakes on the connector's
wakeUrl poke (decisions.md Q3=C', D1-D13).
- gateway/scale_to_zero.py: pure helpers — scale_to_zero_enabled (the NAS
Labs HERMES_SCALE_TO_ZERO stamp, D11/Q8=A), parse_idle_timeout_seconds
(config.yaml gateway.scale_to_zero.idle_timeout_minutes, D2),
messaging_is_relay_only_or_absent (F6/D1), should_arm (D1/D11/§3.4(1)),
is_idle (D2/D3/F7).
- gateway/run.py: _last_inbound_at clock stamped on user inbound in
_handle_message (F13); the arm-gate + idle predicate + the
_scale_to_zero_watcher dormant sequence (mark draining -> adapter
go_dormant() -> cooldown), started only when armed. Deliberately NOT the
stop path and NOT mark_resume_pending (F12/D13).
- tools/process_registry.py: has_any_active() for the bg-work guard (D3/F7).
- hermes_cli/config.py: gateway.scale_to_zero.idle_timeout_minutes default 5.
Tests: 38 pure-logic + 6 watcher (incl. bg-work regression guard proven RED).
Full relay + scale-to-zero suites: 184 passed. The 20 unrelated failures in
the broader run are PRE-EXISTING on origin/main (custom-provider/tools tests),
confirmed via a pristine baseline worktree.
Ben Barclay