# REPORT — R-100: record the last SUCCESS, not just the last attempt (v0.181.0) (2026-07-28)

**Overwritten** per the standing rule. Controller **v0.180.0 → v0.181.0** — the **producer** half of
R-100, shipped and deployed BEFORE the hub so the consumer never reads a field nothing sends.
Consumer: hub **v0.80.0**. Full arc, Phase 0 answers and the live proof: `felhom.eu/REPORT-r100.md`.

## Baselines (reconfirmed, not copied)
`felhom-controller 4056fec` = origin/main, clean; controller 0.180.0 live on both boxes; hub 0.79.0
(manifest and running pod); agent 0.110.0.

## What changed here

`OffboxTarget` gains **`LastSuccess`** (RFC3339), carried to the hub on the offsite report as
`last_success`. `LastRun` is written **unconditionally** at the end of every run including failures — it
records an **attempt**, so "how long since `LastRun`" answers "how long since we last TRIED", which is
not the question the hub's freshness verdict was asking of it.

The rule is a pure function, called unconditionally beside the `LastRun` write:

```go
func offboxAnchorAfterRun(prev, at string, runErr error) string {
	if runErr != nil { return prev } // failures neither advance nor clear the anchor
	return at
}
```

Both directions are distinct bugs and both are pinned: a failure must not **advance** it (the original
defect) and must not **clear** it (one bad night making an established tier read as never-succeeded —
the mirror-image over-correction, and on the hub side the newborn-box path).

**Why not simply `LastStatus == "error" ⇒ stale`:** that is the tempting one-line fix and it pages on
every transient blip — the F-A1 noise mode that trains an operator to ignore the alarm. Anchoring on the
last success tolerates one bad night and catches a persistent one, using the threshold that already
exists. No new knob.

## Two silent-wipe sites, found and closed

Both are the "seam built but never wired" shape — the field exists, the writer sets it, and an unrelated
routine path zeroes it. Neither would have surfaced until the hub's verdict changed, days later.

- **`offboxConfigHandler`** rebuilds the target from the form and copies runtime status across field by
  field, so an ordinary settings save (edit the host, edit the path) would have erased the anchor.
- **`ApplyOffsiteTarget`** does the same on a hub re-apply — an established tier reset to "never
  succeeded" every time the hub re-pushed its descriptor.

## A hollow test of my own, caught by red-proofing it

The first version of `TestOffboxLastSuccess_OnlyAdvancesOnSuccess` re-implemented the rule in a local
closure. Mutating the production code left it **green** — it asserted my model, not the system. That is
what the extraction to `offboxAnchorAfterRun` is for: the test now calls the real rule and the red-proof
bites.

## Red-proofs — all observed failing
| red-proof | observed failure |
|---|---|
| drop the `runErr` guard | `a FAILED run advanced LastSuccess to "2026-07-21T02:15:00Z" — that is the R-100 defect in mirror image` |
| always return `prev` | `a successful run did not advance the anchor` |
| drop `LastSuccess` from the wire | `OffboxReportStatus dropped LastSuccess — the hub would degrade forever on a controller that has it` |
| drop the handler preservation | `a settings save erased LastSuccess (got "") — the tier would read as never-succeeded` |

`go build`, `go vet ./...`, `go test ./...` — 27 packages, `rc=0`, run separately from the commit.

## Live, on demo-hp and demo-felhom
```
demo-hp   success run  → ok     last_run=11:24:20Z  last_success=11:24:20Z
demo-hp   settings save (port 23→2) → last_success PRESERVED 11:24:20Z   ← the wipe-site fix, live
demo-hp   failing run  → error  last_run=11:25:48Z  last_success=11:24:20Z  ← ANCHOR HELD
demo-felhom healthy run→ ok     last_run=11:29:22Z  last_success=11:29:22Z  ← advanced
```
Both shapes reached the hub. The failure was induced with a **closed port** (creates nothing, touches no
data) and the config was restored field by field. `peti-felhom` was never touched.

**Not proven live:** the hub's 48h staleness threshold itself — that is unit-tested with an injected
clock and would take days to observe live.

## Deployed
`felhom-controller` **0.181.0** on **demo-hp** and **demo-felhom**, both `Up (healthy)`.

## NOT yet live-validated (carried forward)
- The 48h threshold, and with it an actually-observed `offsite_stale` firing from a stale anchor.
- **R-101** (filed today) — Tier-2 `LastRun` is also written on failure and three customer surfaces
  render it without a status, incl. the restore-confirm dialog.
- **Fault 4** — restic transport interruption; the closed-port injection sidesteps it, not solves it.
- **R-99** — prune never removes phantom snapshots.