diff --git a/docker-dev/seed/seed-clusters.sql b/docker-dev/seed/seed-clusters.sql
index ce15c214..a4ce9d7e 100644
--- a/docker-dev/seed/seed-clusters.sql
+++ b/docker-dev/seed/seed-clusters.sql
@@ -157,23 +157,35 @@ IF NOT EXISTS (SELECT 1 FROM dbo.DriverInstance WHERE DriverInstanceId = 'MAIN-g
 -- Name to address the MXAccess item. The Galaxy driver subscribes via the
 -- "FolderPath.Name" MXAccess reference form; OPC UA browse path is the
 -- equivalent "FolderPath/Name" under the SystemPlatform namespace.
+--
+-- Idempotency: each insert is guarded on the UX_Tag_FolderPath key
+-- (DriverInstanceId, FolderPath, Name WHERE EquipmentId IS NULL), NOT TagId.
+-- The Galaxy driver auto-materialises these same folder-path tags at runtime
+-- under its own generated TagIds, so a TagId-only guard would pass on a re-run
+-- and then collide on UX_Tag_FolderPath, making cluster-seed exit 1.
 ------------------------------------------------------------------------------
 
-IF NOT EXISTS (SELECT 1 FROM dbo.Tag WHERE TagId = 'MAIN-galaxy-TestMachine_001-TestAlarm001')
+IF NOT EXISTS (SELECT 1 FROM dbo.Tag
+               WHERE DriverInstanceId = 'MAIN-galaxy-mxgw' AND FolderPath = 'TestMachine_001'
+                 AND Name = 'TestAlarm001' AND EquipmentId IS NULL)
     INSERT INTO dbo.Tag
         (TagRowId, TagId, DriverInstanceId, DeviceId, EquipmentId, Name, FolderPath, DataType, AccessLevel, WriteIdempotent, PollGroupId, TagConfig)
     VALUES
         (NEWID(), 'MAIN-galaxy-TestMachine_001-TestAlarm001', 'MAIN-galaxy-mxgw', NULL, NULL,
          'TestAlarm001', 'TestMachine_001', 'Boolean', 0, 0, NULL, N'{}');
 
-IF NOT EXISTS (SELECT 1 FROM dbo.Tag WHERE TagId = 'MAIN-galaxy-TestMachine_001-TestAlarm002')
+IF NOT EXISTS (SELECT 1 FROM dbo.Tag
+               WHERE DriverInstanceId = 'MAIN-galaxy-mxgw' AND FolderPath = 'TestMachine_001'
+                 AND Name = 'TestAlarm002' AND EquipmentId IS NULL)
     INSERT INTO dbo.Tag
         (TagRowId, TagId, DriverInstanceId, DeviceId, EquipmentId, Name, FolderPath, DataType, AccessLevel, WriteIdempotent, PollGroupId, TagConfig)
     VALUES
         (NEWID(), 'MAIN-galaxy-TestMachine_001-TestAlarm002', 'MAIN-galaxy-mxgw', NULL, NULL,
          'TestAlarm002', 'TestMachine_001', 'Boolean', 0, 0, NULL, N'{}');
 
-IF NOT EXISTS (SELECT 1 FROM dbo.Tag WHERE TagId = 'MAIN-galaxy-TestMachine_001-TestAlarm003')
+IF NOT EXISTS (SELECT 1 FROM dbo.Tag
+               WHERE DriverInstanceId = 'MAIN-galaxy-mxgw' AND FolderPath = 'TestMachine_001'
+                 AND Name = 'TestAlarm003' AND EquipmentId IS NULL)
     INSERT INTO dbo.Tag
         (TagRowId, TagId, DriverInstanceId, DeviceId, EquipmentId, Name, FolderPath, DataType, AccessLevel, WriteIdempotent, PollGroupId, TagConfig)
     VALUES