diff --git a/packages/core/src/schema/nodes/column.ts b/packages/core/src/schema/nodes/column.ts
index 78a52126..de411604 100644
--- a/packages/core/src/schema/nodes/column.ts
+++ b/packages/core/src/schema/nodes/column.ts
@@ -159,6 +159,9 @@ export const ColumnNode = BaseNode.extend({
   bracePlateEnabled: z.boolean().default(true),
   material: MaterialSchema.optional(),
   materialPreset: z.string().optional(),
+  // Unified paint-slot refs (`scene:`/`library:` MaterialRef per slot id),
+  // matching the slot model items/slab/shelf use. Absent = declared default.
+  slots: z.record(z.string(), z.string()).optional(),
 }).describe(dedent`
   Column node - used to represent structural or decorative pillars/columns.
   - style: visual approach such as plain, lathe-turned, carved, or cluster
diff --git a/packages/core/src/schema/nodes/elevator.ts b/packages/core/src/schema/nodes/elevator.ts
index 75639387..d1c97b49 100644
--- a/packages/core/src/schema/nodes/elevator.ts
+++ b/packages/core/src/schema/nodes/elevator.ts
@@ -16,6 +16,9 @@ export const ElevatorNode = BaseNode.extend({
   type: nodeType('elevator'),
   material: MaterialSchema.optional(),
   materialPreset: z.string().optional(),
+  // Unified paint-slot refs (`scene:`/`library:` MaterialRef per slot id),
+  // matching the slot model items/slab/shelf use. Absent = declared default.
+  slots: z.record(z.string(), z.string()).optional(),
   position: z.tuple([z.number(), z.number(), z.number()]).default([0, 0, 0]),
   // Rotation around the Y axis in radians.
   rotation: z.number().default(0),
diff --git a/packages/core/src/schema/nodes/fence.ts b/packages/core/src/schema/nodes/fence.ts
index 40875717..1818d007 100644
--- a/packages/core/src/schema/nodes/fence.ts
+++ b/packages/core/src/schema/nodes/fence.ts
@@ -11,6 +11,9 @@ export const FenceNode = BaseNode.extend({
   type: nodeType('fence'),
   material: MaterialSchema.optional(),
   materialPreset: z.string().optional(),
+  // Unified paint-slot refs (`scene:`/`library:` MaterialRef per slot id),
+  // matching the slot model items/slab/shelf use. Absent = declared default.
+  slots: z.record(z.string(), z.string()).optional(),
   start: z.tuple([z.number(), z.number()]),
   end: z.tuple([z.number(), z.number()]),
   height: z.number().default(1.8),
diff --git a/packages/core/src/schema/nodes/stair.ts b/packages/core/src/schema/nodes/stair.ts
index a0c68fe1..abc1fe54 100644
--- a/packages/core/src/schema/nodes/stair.ts
+++ b/packages/core/src/schema/nodes/stair.ts
@@ -31,6 +31,9 @@ export const StairNode = BaseNode.extend({
   treadMaterialPreset: z.string().optional(),
   sideMaterial: MaterialSchema.optional(),
   sideMaterialPreset: z.string().optional(),
+  // Unified paint-slot refs (`scene:`/`library:` MaterialRef per slot id),
+  // matching the slot model items/slab/shelf use. Absent = declared default.
+  slots: z.record(z.string(), z.string()).optional(),
   position: z.tuple([z.number(), z.number(), z.number()]).default([0, 0, 0]),
   // Rotation around Y axis in radians
   rotation: z.number().default(0),