# S1 Handoff Gate

`make s1-handoff` is the operator-facing gate from host substrate (S1) to the
cluster layer (S2). It validates inventory and baseline contracts, requires a
clean checkout, runs the applicable Goss profile for every selected host, and
emits a metadata-only JSON receipt under `reports/`.

A passing receipt pins:

- source revision and inventory digest
- every selected host and its baseline profile
- observed time and 24-hour default freshness boundary
- per-host exit status
- SHA-256 digests of the resulting TAP evidence

Any failed host fails the aggregate. A passing receipt without host evidence is
invalid. `make s1-handoff-dry-run` validates local inputs but records
`status: not-run`; it cannot authorize S2 handoff.

The current profiles are:

- `Railiance01`: `ufw-managed`
- `CoulombCore`: `external-firewall`, which verifies the declared iptables
  INPUT default-drop replacement control

The gate is read-only on managed hosts. Before connecting,
`scripts/handoff_contract.py` proves that its playbook contains only remote
`stat`, `assert`, and the fixed Goss validation command, and pins the Goss
assertion commands themselves to a reviewed read-only set. It renders each
selected profile locally and fails if the installed
`/etc/goss/baseline.yaml` digest differs, instead of refreshing it implicitly.
TAP and the aggregate receipt are written only beneath the controller's
ignored `reports/` path.

If a surface is stale, the operator must review it and separately approve
`make verify-refresh-host`; that change cannot be smuggled through a handoff
run. The handoff command does not run Terraform, change provider resources,
rotate credentials, converge a role, write remote files, or change services.

Receipts validate with:

```bash
python3 scripts/s1_receipt.py reports/s1-handoff-*.json
```

S2 should accept only `status: pass` receipts whose source and inventory match
the intended handoff and whose `fresh_until` has not elapsed.