# STATE-WP-0091 — release headroom and demand handoff

Date: 2026-09-14

## T01 — preflight

`scripts/release_headroom_preflight.py` is on the promotion path
(`make railiance-state-hub-headroom`, `PROMOTE.md` step 0). It is read-only.

Proved against fixtures of the 2026-09-10 incident:

| Case | Remaining | Result |
| --- | --- | --- |
| Revision 61 | 65m | refuse API 100m surge |
| Revision 63 | 105m | narrowly sufficient; not factory admission |
| 105m plus 50m unrelated pending | 55m effective | refuse |

Atomic rollback stays `--atomic`. Requests are not lowered by this tool.

Live kubectl on 2026-09-14 refused: remaining 15m, pending unrelated 25m,
migrate hook 50m unmet. The preflight is doing its job on the current node.

## T02 — MCP demand and margin

STATE-WP-0090 recorded 1,078 five-minute samples in a seven-day window
(partial coverage): MCP p99 2.35m, peak 30.45m. The MCP request was cut
50m → 10m; limit 500m, memory and replicas unchanged.

That sample set is still not a week of complete coverage. It is enough to
say:

- 10m request is above p99 and below peak; bursts still use the 500m limit.
- 105m node remainder is only 5m above the API surge. Concurrent MCP surge
  (10m) or any unrelated pending pod ≥ 6m makes it insufficient.
- **Durable release margin for State Hub:** remaining CPU after current
  allocations must cover API surge 100m + migrate hook 50m sequenced
  separately, and must refuse when unrelated pending demand would consume
  the 5m sliver. Do not treat 105m as shared-capacity admission.

Shared allocation and provisioning stay with other owners. Receiving records:

- `RAIL-BS-WP-0014` (railiance-cluster) — node remaining vs surge, pending pods
- `RESOURCE-WP-0007` (resource-control) — reef-railiance-k3s portfolio, not admission
- `RPF-WP-0041` (railiance-platform) — no platform provisioning change from 105m
- `CUST-WP-0071` already owns weekly fleet allocation review

HFACT T01/T04 factory demand is not admitted by this 105m figure.