diff --git a/docs/CURRENT-STATE.md b/docs/CURRENT-STATE.md
index 813823b..4fd56c8 100644
--- a/docs/CURRENT-STATE.md
+++ b/docs/CURRENT-STATE.md
@@ -1506,6 +1506,27 @@
   standup as a definition-of-done item (set the ruled hostname BEFORE commissioning, so MAAS,
   the OS and the ruled name agree from the start), and reaches DC0 at its next node
   redeploy.**
+  **MODEL-CONFIG DURABILITY -- `apt-mirror` SET AS A CONTROLLER MODEL-DEFAULT 2026-07-31
+  (operator: "Yes, set the defaults").** The teardown demonstrated the gap: `destroy-model`
+  takes the model config with it, so Step 3.5's `apt-mirror` (and the spaces work) vanished,
+  and **NOTHING in the repo would have caught it** -- the next deploy would have failed on
+  package fetches and read like a mirror fault rather than a missing model setting. That is
+  the "prose cannot close a stage" class: Step 3.5 is RUNBOOK PROSE with no gate.
+  MEASURED: `juju model-defaults` carries `apt-mirror`, `snap-https-proxy`, `snap-store-proxy`
+  and `snap-store-proxy-url`, all previously unset at Controller level. Set and read back:
+  `apt-mirror ... Controller http://10.12.8.4/ubuntu`. **Defaults are inherited by NEW models
+  only, not applied retroactively** -- which suits the pending fresh `add-model`.
+  **PER-DC BY CONSTRUCTION AND THAT IS WHY IT FITS: D-104 gives each DC its OWN Juju
+  controller**, and these values are per-DC (`10.12.8.4` vs `10.12.68.4`), so per-controller
+  defaults map onto per-DC values with no cross-DC coupling.
+  **THE SNAP KEY IS DELIBERATELY NOT SET YET** -- the proxy does not exist, and pointing
+  `snap-https-proxy` at a dead address would make snap installs fail WORSE than they do now
+  (connecting to nothing rather than attempting direct). It lands with the proxy.
+  **OWED, and it is the durability half rather than the mechanism half: a site-keyed
+  `dc-model-defaults.sh` with a `check`**, so the values are VERIFIED at every DC standup
+  rather than remembered. Roosevelt shape: fold these into D-136's per-DC render pipeline so
+  model-config comes from the same per-DC values files that already produce the overlays.
+  **DC1 LESSON: set model-defaults at controller bootstrap, BEFORE its first `add-model`.**
   **memcached SCALED to 3 in `overlays/dc-ha-scaleup.yaml`** (operator-directed 2026-07-31);
   its exclusion comment is RE-POINTED rather than left stale. **`ceph-rbd-mirror` is PINNED,
   NOT SETTLED** -- gap register **item 22** carries four options and the recommendation