diff --git a/internal/inventory/migrations/0048-the-artifact-store-seat-is-named-for-its-scope.sql b/internal/inventory/migrations/0048-the-artifact-store-seat-is-named-for-its-scope.sql
index 26f8a72..2ac3538 100644
--- a/internal/inventory/migrations/0048-the-artifact-store-seat-is-named-for-its-scope.sql
+++ b/internal/inventory/migrations/0048-the-artifact-store-seat-is-named-for-its-scope.sql
@@ -5,7 +5,20 @@
 -- than for the mesh; ADR 0121 decided the rename and deferred it because a delivering seat that stops
 -- resolving mid-flight takes a provision away from every consumer. ADR 0122 removed that risk: a seat's
 -- former name is an alias that resolves to it forever, a held record follows the rename by cascade, and
--- a claim written with the old name still holds. So the rename is one update and one alias.
+-- a claim written with the old name still holds.
+--
+-- **Both rows may exist when this runs.** A controller whose compiled defaults already carry the new
+-- name seeds it as a new seat the moment it can, and on the mesh this was written for that happened
+-- before the rename: the first form of this migration renamed into a duplicate key and the control
+-- node's prepare failed on every attempt (2026-09-30). So: if the new row is already there, the old
+-- row's holding moves to it and the old row goes; otherwise the old row is renamed. Either way the old
+-- name becomes an alias.
+update seat_holding set seat = 'mesh-artifact-store'
+  where seat = 'the-artifact-store'
+    and exists (select 1 from seat where name = 'mesh-artifact-store');
+delete from seat
+  where name = 'the-artifact-store'
+    and exists (select 1 from seat where name = 'mesh-artifact-store');
 update seat set name = 'mesh-artifact-store' where name = 'the-artifact-store';
 insert into seat_alias (alias, seat) values ('the-artifact-store', 'mesh-artifact-store')
   on conflict (alias) do update set seat = excluded.seat;