docs(runbook): replace the laptop cell in prometheus (#454)

README.md

@@ -93,7 +93,7 @@ documents for different readers.
   from `compose.yaml` too, so an image that is not pinned there cannot be run
   at all.
 - **Documented decisions and runbooks.** 42 ADRs covering what was chosen
-  and what was rejected — including the costs accepted knowingly; 27
+  and what was rejected — including the costs accepted knowingly; 28
   runbooks for the operations that are easy to get wrong at 1am, one of which
   is the handover page a successor reads first.
 

docs/hardware.md

@@ -392,21 +392,26 @@ revisions of this repository treated `shiva` as the hypervisor itself.
   ([#76](https://github.com/Gerrrt/HomeLab/issues/76))
 - A1437 battery cell for `prometheus`[^A1437] — the pack that fits the
   `A1425`, the late-2012 Retina 13" in the Compute table — bought new
-  2026-09-13, in transit. A consumable and not an upgrade: it is the one
+  2026-09-13, **delivered 2026-09-18 and not yet fitted.** A consumable and
+  not an upgrade: it is the one
   exception the roadmap's *Never* line names, bought because the estate's
   mains-cut path rests on this cell and the failure mode of a
   thirteen-year-old lithium cell on a shelf is swelling
   ([#454](https://github.com/Gerrrt/HomeLab/issues/454)). The listing calls
   it genuine and its brand field says unbranded, so it is recorded as a
-  compatible cell, not an Apple part, until it is in hand. The cell it
+  compatible cell, not an Apple part. That wording was written to be settled
+  once the part could be looked at, which it now can: the cell arrived
+  2026-09-18 and this line stays as it is until someone reads the pack's own
+  markings and says otherwise. The cell it
   replaces read 94 % of design capacity after 108 cycles on 2026-09-12, which
   is above `HostBatteryHealthLow`'s 80 % — it is bought on age, not on the
   alert. Nothing in the Compute table changes; a cell is not a spec.
   **Checked at the fit, not assumed:** `charge_full` at or near
   `charge_full_design` and a cycle count reading low, then mains pulled and
   the host staying up with `HostOnBattery` firing — the property the cell is
   there for, and untested since the machine was commissioned
-  ([`fit-the-ups-battery.md`](runbooks/fit-the-ups-battery.md)). `oracle`'s
+  ([`replace-the-laptop-cell.md`](runbooks/replace-the-laptop-cell.md), which
+  also carries the stack-down window and the old cell's disposal). `oracle`'s
   cell reads 72 % and is second in line, unbought.
 - ViewSonic N1700W LCD, used as a rack console via the KVM
 - RJ45 Cat6 in-line couplers[^Couplers]

docs/observability.md

@@ -437,7 +437,7 @@ argument and for what to do when it exits 1.
 
 | File | Covers |
 | --- | --- |
-| `host.rules.yaml` | Instance down, predictive disk fill, memory, load, clock skew, reboots — and, for the two laptops, whether the shelf is on mains and whether the cell that carries them through a cut is still worth relying on ([#454](https://github.com/Gerrrt/HomeLab/issues/454)); and whether the wiki's drift check on `oracle` is still running ([#470](https://github.com/Gerrrt/HomeLab/issues/470)) |
+| `host.rules.yaml` | Instance down, predictive disk fill, memory, load, clock skew, reboots — and, for the two laptops, whether the shelf is on mains and whether the cell that carries them through a cut is still worth relying on ([#454](https://github.com/Gerrrt/HomeLab/issues/454), and [`runbooks/replace-the-laptop-cell.md`](runbooks/replace-the-laptop-cell.md) for the swap); and whether the wiki's drift check on `oracle` is still running ([#470](https://github.com/Gerrrt/HomeLab/issues/470)) |
 | `network.rules.yaml` | SNMP reachability, pf not running, state table, switch links, iLO hardware and Smart Array cache. `shiva`'s Smart Storage Battery read failed from 2026-08-18 until it was replaced on 2026-09-02, with the array in write-through as a result, so stored metrics before that date show the failed pack — `IloBatteryCondition` names the spare part to order, and the controller rollups are deliberately read at *failed* rather than *degraded* ([#76](https://github.com/Gerrrt/HomeLab/issues/76)) |
 | `ups.rules.yaml` | On battery, low battery, runtime, load, temperature. A pack was fitted on 2026-08-28 and passed its self-test, so these read real hardware; stored metrics older than that date are the card's fabricated values — see [`runbooks/fit-the-ups-battery.md`](runbooks/fit-the-ups-battery.md) |
 | `containers.rules.yaml` | Restart loops, OOM kills, memory, throttling |

docs/runbooks/fit-the-ups-battery.md

@@ -90,11 +90,16 @@ hosts, and `host.rules.yaml` reads it — `HostBatteryHealthLow` when a cell's
 after 108 cycles, `oracle` 72 %), `HostOnBattery` when the mains adapter loses
 input, `HostBatteryNotReported` when a laptop stops reporting a cell. The cell
 for `prometheus`, an A1437, was bought 2026-09-13 and is recorded in
-[`hardware.md`](../hardware.md#accessories). After a cell is swapped,
-`charge_full` should sit at or near `charge_full_design` and the cycle count
-read low. Then pull that laptop's mains and confirm the host
-stays up and `HostOnBattery` fires: that is the property the cell is there for,
-and it had not been tested since the machine was commissioned.
+[`hardware.md`](../hardware.md#accessories). The swap and the tests that prove
+it are [`replace-the-laptop-cell.md`](replace-the-laptop-cell.md), which is
+where the baseline, the disposal and the stack-down window are written down —
+that cell is glued into the machine running this stack, so fitting it blinds
+the estate for the length of the job, which is the one cost this runbook's own
+pack did not carry. What it proves is the same shape as step 5 here:
+`charge_full` at or near `charge_full_design` and the cycle count reading low,
+then that laptop's mains pulled with the host staying up and `HostOnBattery`
+firing — the property the cell is there for, and untested since the machine was
+commissioned.
 
 ## Before you start