diff --git a/packages/core/src/schema/nodes/level.test.ts b/packages/core/src/schema/nodes/level.test.ts
index e9e0efa9..f950f122 100644
--- a/packages/core/src/schema/nodes/level.test.ts
+++ b/packages/core/src/schema/nodes/level.test.ts
@@ -50,10 +50,10 @@ describe('LevelNode', () => {
   })
 
   test('accepts level child IDs minted by plugins', () => {
-    expect(
-      LevelNode.parse({
-        children: ['tree_plugin-child', 'flower_plugin-child', 'grass_plugin-child'],
-      }).children,
-    ).toEqual(['tree_plugin-child', 'flower_plugin-child', 'grass_plugin-child'])
+    const children = LevelNode.parse({
+      children: ['tree_plugin-child', 'flower_plugin-child', 'grass_plugin-child'],
+    }).children as string[]
+
+    expect(children).toEqual(['tree_plugin-child', 'flower_plugin-child', 'grass_plugin-child'])
   })
 })
diff --git a/packages/core/src/schema/nodes/level.ts b/packages/core/src/schema/nodes/level.ts
index 1055648b..0360598f 100644
--- a/packages/core/src/schema/nodes/level.ts
+++ b/packages/core/src/schema/nodes/level.ts
@@ -1,13 +1,63 @@
 import dedent from 'dedent'
 import { z } from 'zod'
 import { BaseNode, nodeType, objectId } from '../base'
+import type { CeilingNode } from './ceiling'
+import type { ColumnNode } from './column'
+import type { DuctFittingNode } from './duct-fitting'
+import type { DuctSegmentNode } from './duct-segment'
+import type { DuctTerminalNode } from './duct-terminal'
+import type { FenceNode } from './fence'
+import type { GuideNode } from './guide'
+import type { HvacEquipmentNode } from './hvac-equipment'
+import type { ItemNode } from './item'
+import type { LinesetNode } from './lineset'
+import type { LiquidLineNode } from './liquid-line'
+import type { MeasurementNode } from './measurement'
+import type { PipeFittingNode } from './pipe-fitting'
+import type { PipeSegmentNode } from './pipe-segment'
+import type { PipeTrapNode } from './pipe-trap'
+import type { RoofNode } from './roof'
+import type { ScanNode } from './scan'
+import type { ShelfNode } from './shelf'
+import type { SlabNode } from './slab'
+import type { SpawnNode } from './spawn'
+import type { StairNode } from './stair'
+import type { WallNode } from './wall'
+import type { ZoneNode } from './zone'
+
+type CoreLevelChildId =
+  | WallNode['id']
+  | FenceNode['id']
+  | ColumnNode['id']
+  | ItemNode['id']
+  | ZoneNode['id']
+  | SlabNode['id']
+  | CeilingNode['id']
+  | RoofNode['id']
+  | StairNode['id']
+  | ScanNode['id']
+  | GuideNode['id']
+  | MeasurementNode['id']
+  | SpawnNode['id']
+  | ShelfNode['id']
+  | DuctSegmentNode['id']
+  | DuctFittingNode['id']
+  | DuctTerminalNode['id']
+  | HvacEquipmentNode['id']
+  | LinesetNode['id']
+  | LiquidLineNode['id']
+  | PipeSegmentNode['id']
+  | PipeFittingNode['id']
+  | PipeTrapNode['id']
+
+const LevelChildId = z.string().transform((id) => id as CoreLevelChildId)
 
 export const LevelNode = BaseNode.extend({
   id: objectId('level'),
   type: nodeType('level'),
   // The node registry owns child-kind validity. Persisted level relationships
   // must also admit IDs minted by plugins that core cannot enumerate.
-  children: z.array(z.string()).default([]),
+  children: z.array(LevelChildId).default([]),
   // Specific props
   level: z.number().default(0),
 }).describe(