diff --git a/docs/SESSIONS.md b/docs/SESSIONS.md
index baef4a7e6..7350dd325 100644
--- a/docs/SESSIONS.md
+++ b/docs/SESSIONS.md
@@ -743,3 +743,4 @@ are never rewritten or removed; corrections are new entries.
 2026-10-12T04:05Z | darkwing | row 83 (#1576) round 1 review | approve, comment 27721; 6 of 8 mutants killed, 1 equivalent and 1 usage-text survivor; queue rev 633 in cc03711e, packet 3094623a
 2026-10-12T04:06:07Z | filbert | row 83 (#1576) round 1 review | approve, comment 27722, rev 634 (41aee177); gate green on d13b9300+patch, 12/12 own mutants killed, 16/16 no-send renders identical to base, two non-blocking notes
 2026-10-12T04:12:27Z | sage | row 83 (#1576) gate and landing | gate green 04:07:30Z-04:10:47Z on 23d38413+patch; landed 1a8ba587, verify-commit 4 paths, done rev 635 (7a4ca67b, swept only rev 635), #1576 closed 27728; four follow-ups listed for after the cutover
+2026-10-12T04:14:04Z | sage | decision 103, cutover reinstall | Mos runs the mosaic.woltje.com install at the go after ops-01's path patch, then restarts under decision 102; preview host mosaic-preview.woltje.com confirmed by Mos sage-0070 from the route proposal (0d67e926)
diff --git a/docs/plans/2026-09-26_lead-decisions.md b/docs/plans/2026-09-26_lead-decisions.md
index 33497a8de..32fe6aff0 100644
--- a/docs/plans/2026-09-26_lead-decisions.md
+++ b/docs/plans/2026-09-26_lead-decisions.md
@@ -2253,3 +2253,35 @@ which stay with him. Each item names who decided it and what happened.
     - The tradeoff: the human proof now rests on Jason's grant to one
       named seat, not on his own shell. In exchange, a cutover restart
       no longer waits for Jason to be at a terminal.
+
+103. **Mos runs the cutover reinstall for mosaic.woltje.com (2026-10-12).**
+    Mos (sage-0070) confirmed the preview install host
+    mosaic-preview.woltje.com from ops-01's route proposal (sha256
+    0d67e926..., line 136, the file rev-sol-01 is reviewing). At the go,
+    `overlays/cutover` matches both names (line 138), and step 7 (line
+    305) restarts the Console with `--public-host mosaic.woltje.com`.
+    `serve` takes one public host, so from then on the preview name
+    answers 403. The go therefore needs a second install, which no row
+    or decision named.
+    - Mos runs it, at the go, in this order: ops-01's path patch; then
+      from /mnt/storage/src/mosaic-stack, at a commit containing
+      1a8ba587, `scripts/webui-service.sh install --public-host
+      mosaic.woltje.com --auth-header X-authentik-username --allow-user
+      jason.woltje --send`; then `systemctl --user restart
+      mosaic-webui` under decision 102; then
+      `scripts/webui-service.sh status`, which must show "send: on"
+      and a healthy /healthz.
+    - If the install exits nonzero, Mos doesn't restart. The running
+      unit keeps the preview host, and Mos reports to Sage.
+    - Undo: rerun the install with `--public-host
+      mosaic-preview.woltje.com`, then restart. That pairs with
+      ops-01's route revert.
+    - Install only writes the unit and runs daemon-reload, which any
+      agent may do. Mos runs it because the restart that follows is
+      Mos's anyway, and a handoff in the go window would only add a
+      wait. Sage installs the preview unit beforehand, once rev-sol-01
+      passes.
+    - Decision 101's uid reinstall stays a separate step after this
+      one, with the same command and the hex guard.
+    - Row 83 is closed, and its brief stays as pinned. This decision
+      is the record of the cutover install steps.