diff --git a/packages/editor/src/components/ui/panels/door-panel.tsx b/packages/editor/src/components/ui/panels/door-panel.tsx
index c46838de..599d1e21 100644
--- a/packages/editor/src/components/ui/panels/door-panel.tsx
+++ b/packages/editor/src/components/ui/panels/door-panel.tsx
@@ -109,7 +109,6 @@ function isSameDoorValue(current: unknown, next: unknown): boolean {
 export function DoorPanel() {
   const selectedId = useViewer((s) => s.selection.selectedIds[0])
   const setSelection = useViewer((s) => s.setSelection)
-  const updateNode = useScene((s) => s.updateNode)
   const deleteNode = useScene((s) => s.deleteNode)
   const setMovingNode = useEditor((s) => s.setMovingNode)
   const previewRef = useRef<{
@@ -124,9 +123,11 @@ export function DoorPanel() {
     selectedId ? (s.nodes[selectedId as AnyNode['id']] as DoorNode | undefined) : undefined,
   )
 
+  // Panel slider-drag fix recipe (plans/editor-node-registry.md). Without
+  // it, the 29+ SliderControls in this panel would loop on drag.
   const handleUpdate = useCallback(
     (updates: Partial<DoorNode>) => {
-      if (!(selectedId && node)) return
+      if (!selectedId) return
       const liveNode = useScene.getState().nodes[selectedId as AnyNodeId]
       if (liveNode?.type !== 'door') return
 
@@ -139,12 +140,12 @@ export function DoorPanel() {
       if ('operationState' in updates || 'swingAngle' in updates || 'doorType' in updates) {
         useInteractive.getState().removeDoorOpenState(selectedId as AnyNodeId)
       }
-      updateNode(selectedId as AnyNode['id'], updates)
+      useScene.getState().updateNode(selectedId as AnyNode['id'], updates)
       const scene = useScene.getState()
       scene.dirtyNodes.add(selectedId as AnyNodeId)
       if (liveNode.parentId) scene.dirtyNodes.add(liveNode.parentId as AnyNodeId)
     },
-    [selectedId, node, updateNode],
+    [selectedId],
   )
 
   const previewDoorUpdate = useCallback(
@@ -188,10 +189,10 @@ export function DoorPanel() {
       }
       previewRef.current = null
 
-      updateNode(selectedId as AnyNode['id'], { [key]: value } as Partial<DoorNode>)
+      useScene.getState().updateNode(selectedId as AnyNode['id'], { [key]: value } as Partial<DoorNode>)
       scene.dirtyNodes.add(selectedId as AnyNodeId)
     },
-    [selectedId, updateNode],
+    [selectedId],
   )
 
   const handleClose = useCallback(() => {
diff --git a/packages/editor/src/components/ui/panels/window-panel.tsx b/packages/editor/src/components/ui/panels/window-panel.tsx
index b26cf0f0..24b3c5c7 100644
--- a/packages/editor/src/components/ui/panels/window-panel.tsx
+++ b/packages/editor/src/components/ui/panels/window-panel.tsx
@@ -93,7 +93,6 @@ const silllessWindowTypes = new Set<WindowNode['windowType']>(['bay', 'bow'])
 export function WindowPanel() {
   const selectedId = useViewer((s) => s.selection.selectedIds[0])
   const setSelection = useViewer((s) => s.setSelection)
-  const updateNode = useScene((s) => s.updateNode)
   const deleteNode = useScene((s) => s.deleteNode)
   const setMovingNode = useEditor((s) => s.setMovingNode)
   const previewRef = useRef<{
@@ -108,9 +107,11 @@ export function WindowPanel() {
     selectedId ? (s.nodes[selectedId as AnyNode['id']] as WindowNode | undefined) : undefined,
   )
 
+  // Panel slider-drag fix recipe (plans/editor-node-registry.md). Without
+  // it, the 15+ SliderControls in this panel would loop on drag.
   const handleUpdate = useCallback(
     (updates: Partial<WindowNode>) => {
-      if (!(selectedId && node)) return
+      if (!selectedId) return
       const liveNode = useScene.getState().nodes[selectedId as AnyNodeId]
       if (liveNode?.type !== 'window') return
 
@@ -120,12 +121,12 @@ export function WindowPanel() {
       })
       if (!hasChange) return
 
-      updateNode(selectedId as AnyNode['id'], updates)
+      useScene.getState().updateNode(selectedId as AnyNode['id'], updates)
       const scene = useScene.getState()
       scene.dirtyNodes.add(selectedId as AnyNodeId)
       if (liveNode.parentId) scene.dirtyNodes.add(liveNode.parentId as AnyNodeId)
     },
-    [selectedId, node, updateNode],
+    [selectedId],
   )
 
   const previewWindowUpdate = useCallback(
@@ -169,10 +170,12 @@ export function WindowPanel() {
       }
       previewRef.current = null
 
-      updateNode(selectedId as AnyNode['id'], { [key]: value } as Partial<WindowNode>)
+      useScene.getState().updateNode(selectedId as AnyNode['id'], {
+        [key]: value,
+      } as Partial<WindowNode>)
       scene.dirtyNodes.add(selectedId as AnyNodeId)
     },
-    [selectedId, updateNode],
+    [selectedId],
   )
 
   const handleClose = useCallback(() => {
diff --git a/packages/nodes/src/door/definition.ts b/packages/nodes/src/door/definition.ts
new file mode 100644
index 00000000..e5520243
--- /dev/null
+++ b/packages/nodes/src/door/definition.ts
@@ -0,0 +1,76 @@
+import type { NodeDefinition } from '@pascal-app/core'
+import { doorParametrics } from './parametrics'
+import { DoorNode } from './schema'
+
+/**
+ * Door — Phase 5 batch kind. Hosted on walls, cuts holes in them,
+ * animated open/close state.
+ *
+ * Capabilities:
+ *  - **No `movable`**: door's move is bespoke wall-bound drag (slide
+ *    along the wall, snap to wall start/end). Capability-driven dispatch
+ *    keeps legacy `MoveDoorTool`.
+ *  - `selectable`, `duplicable`, `deletable` standard.
+ *
+ * Relations:
+ *  - `parentId` references a wall — re-anchors on wall move (handled by
+ *    `DoorSystem`'s cascade to parent wall).
+ *  - `cascadeDelete: 'children'` — door has no children in v1.
+ *
+ * Renderer + system: wrap-export legacy `DoorRenderer` + bundle
+ * `DoorSystem` + `DoorAnimationSystem`.
+ *
+ * Tool field absent: door placement / move tools wired through editor
+ * state, not registry dispatch. Legacy DoorTool / MoveDoorTool continue.
+ */
+export const doorDefinition: NodeDefinition<typeof DoorNode> = {
+  kind: 'door',
+  schemaVersion: 1,
+  schema: DoorNode,
+  category: 'structure',
+
+  // Leverage the schema's zod `.default()` annotations to compute the
+  // full default shape — door has 40+ fields, listing them inline would
+  // duplicate the schema. Parse a minimal stub, drop id/type, return rest.
+  defaults: () => {
+    const stub = DoorNode.parse({ id: 'door_default' as never, type: 'door' })
+    const { id: _id, type: _type, ...rest } = stub
+    return rest
+  },
+
+  capabilities: {
+    selectable: { hitVolume: 'bbox' },
+    duplicable: true,
+    deletable: true,
+  },
+
+  parametrics: doorParametrics,
+
+  renderer: {
+    kind: 'parametric',
+    module: () => import('./renderer'),
+  },
+  system: {
+    module: () => import('./system'),
+    // Priority 3 mirrors the legacy DoorSystem (after animation at 2,
+    // before wall mitering at 4).
+    priority: 3,
+  },
+
+  toolHints: [
+    { key: 'Left click', label: 'Place door on wall' },
+    { key: 'Esc', label: 'Cancel' },
+  ],
+
+  presentation: {
+    label: 'Door',
+    description: 'A door cut into a wall. Animated open/close state.',
+    icon: { kind: 'iconify', name: 'lucide:door-open' },
+    paletteSection: 'structure',
+    paletteOrder: 50,
+  },
+
+  mcp: {
+    description: 'A door mounted on a wall, with type / dimensions / hardware options.',
+  },
+}
diff --git a/packages/nodes/src/door/index.ts b/packages/nodes/src/door/index.ts
new file mode 100644
index 00000000..364ea491
--- /dev/null
+++ b/packages/nodes/src/door/index.ts
@@ -0,0 +1,2 @@
+export { doorDefinition } from './definition'
+export { DoorNode } from './schema'
diff --git a/packages/nodes/src/door/parametrics.ts b/packages/nodes/src/door/parametrics.ts
new file mode 100644
index 00000000..6e7dcdb7
--- /dev/null
+++ b/packages/nodes/src/door/parametrics.ts
@@ -0,0 +1,32 @@
+import type { ParametricDescriptor } from '@pascal-app/core'
+import type { DoorNode } from './schema'
+
+/**
+ * Minimal inspector descriptor for door. The legacy `<DoorPanel>` has
+ * 29 SliderControls covering segments, hardware, hinges, panic bar,
+ * opening shape, etc. — too elaborate for the auto-inspector at Stage A.
+ * Legacy panel keeps rendering via the hardcoded `case 'door':` in
+ * panel-manager.tsx. This descriptor only exposes the simple dimension
+ * fields so the registry knows door has parametric data. Phase 5 Stage E
+ * (drop legacy panel) will extend this — likely via
+ * `parametrics.customPanel?` since door has too much non-numeric UI
+ * (segmented controls, presets) to fit the generic auto-UI.
+ */
+export const doorParametrics: ParametricDescriptor<DoorNode> = {
+  groups: [
+    {
+      label: 'Dimensions',
+      fields: [
+        { key: 'width', kind: 'number', unit: 'm', min: 0.5, max: 6, step: 0.05 },
+        { key: 'height', kind: 'number', unit: 'm', min: 1.0, max: 4, step: 0.05 },
+      ],
+    },
+    {
+      label: 'Frame',
+      fields: [
+        { key: 'frameThickness', kind: 'number', unit: 'm', min: 0.01, max: 0.2, step: 0.005 },
+        { key: 'frameDepth', kind: 'number', unit: 'm', min: 0.01, max: 0.3, step: 0.005 },
+      ],
+    },
+  ],
+}
diff --git a/packages/nodes/src/door/renderer.tsx b/packages/nodes/src/door/renderer.tsx
new file mode 100644
index 00000000..519fa4c5
--- /dev/null
+++ b/packages/nodes/src/door/renderer.tsx
@@ -0,0 +1,11 @@
+'use client'
+
+import { DoorRenderer } from '@pascal-app/viewer'
+
+/**
+ * Wrap-export of the legacy `DoorRenderer`. The renderer is 33 lines
+ * (thin placeholder + register + dirty-on-mount) — could be duplicated
+ * but at Stage A re-export is sufficient. Phase 5 Stage F will inline
+ * it here and delete the viewer-side file.
+ */
+export default DoorRenderer
diff --git a/packages/nodes/src/door/schema.ts b/packages/nodes/src/door/schema.ts
new file mode 100644
index 00000000..1f4fac97
--- /dev/null
+++ b/packages/nodes/src/door/schema.ts
@@ -0,0 +1 @@
+export { DoorNode } from '@pascal-app/core'
diff --git a/packages/nodes/src/door/system.tsx b/packages/nodes/src/door/system.tsx
new file mode 100644
index 00000000..c03a1cb0
--- /dev/null
+++ b/packages/nodes/src/door/system.tsx
@@ -0,0 +1,34 @@
+'use client'
+
+import { DoorAnimationSystem, DoorSystem } from '@pascal-app/viewer'
+
+/**
+ * Registry-driven door system bundle. Door has TWO per-frame systems:
+ *
+ *  - **`DoorSystem`** — rebuilds frame / leaf / glass / hardware
+ *    geometry from `dirtyNodes`. Cascades dirty to the parent wall so
+ *    the wall cutout reflects the new door footprint.
+ *  - **`DoorAnimationSystem`** — advances `operationState` (open/close
+ *    angle for hinged, slide offset for sliding/pocket, fold angle for
+ *    folding) at frame priority 2, then marks the door dirty so the
+ *    geometry system rebuilds at priority 3.
+ *
+ * Both are wrapped in `<LegacySystem kind="door">` at the legacy mount
+ * point; with door registered, those wrappers short-circuit and this
+ * bundle takes over.
+ *
+ * Future Phase 5 Stage B: extract the geometry into a pure
+ * `buildDoorGeometry(node, ctx)` and migrate to `def.geometry`. The
+ * animation system stays as `def.system` (it's a real per-frame
+ * concern, not a geometry build).
+ */
+const DoorSystems = () => {
+  return (
+    <>
+      <DoorAnimationSystem />
+      <DoorSystem />
+    </>
+  )
+}
+
+export default DoorSystems
diff --git a/packages/nodes/src/index.ts b/packages/nodes/src/index.ts
index f00a7004..1f9bea25 100644
--- a/packages/nodes/src/index.ts
+++ b/packages/nodes/src/index.ts
@@ -1,10 +1,12 @@
 import type { AnyNodeDefinition, Plugin } from '@pascal-app/core'
 import { ceilingDefinition } from './ceiling'
+import { doorDefinition } from './door'
 import { fenceDefinition } from './fence'
 import { shelfDefinition } from './shelf'
 import { slabDefinition } from './slab'
 import { spawnDefinition } from './spawn'
 import { wallDefinition } from './wall'
+import { windowDefinition } from './window'
 
 /**
  * Built-in plugin bundling every node kind shipped with the Pascal editor.
@@ -34,12 +36,16 @@ export const builtinPlugin: Plugin = {
     fenceDefinition as unknown as AnyNodeDefinition,
     slabDefinition as unknown as AnyNodeDefinition,
     ceilingDefinition as unknown as AnyNodeDefinition,
+    doorDefinition as unknown as AnyNodeDefinition,
+    windowDefinition as unknown as AnyNodeDefinition,
   ],
 }
 
 export { ceilingDefinition } from './ceiling'
+export { doorDefinition } from './door'
 export { fenceDefinition } from './fence'
 export { shelfDefinition } from './shelf'
 export { slabDefinition } from './slab'
 export { spawnDefinition } from './spawn'
 export { wallDefinition } from './wall'
+export { windowDefinition } from './window'
diff --git a/packages/nodes/src/window/definition.ts b/packages/nodes/src/window/definition.ts
new file mode 100644
index 00000000..0ac4eb6d
--- /dev/null
+++ b/packages/nodes/src/window/definition.ts
@@ -0,0 +1,59 @@
+import type { NodeDefinition } from '@pascal-app/core'
+import { windowParametrics } from './parametrics'
+import { WindowNode } from './schema'
+
+/**
+ * Window — Phase 5 batch kind. Mirrors door's shape: hosted on walls,
+ * cuts holes in them, animated open/close state for opening windows.
+ *
+ * Capabilities: no `movable` (wall-bound drag is bespoke). Tool field
+ * absent (legacy WindowTool / MoveWindowTool continue).
+ */
+export const windowDefinition: NodeDefinition<typeof WindowNode> = {
+  kind: 'window',
+  schemaVersion: 1,
+  schema: WindowNode,
+  category: 'structure',
+
+  // Same schema-driven defaults trick as door: parse a stub, strip
+  // id/type. Window also has many fields with zod `.default()` set.
+  defaults: () => {
+    const stub = WindowNode.parse({ id: 'window_default' as never, type: 'window' })
+    const { id: _id, type: _type, ...rest } = stub
+    return rest
+  },
+
+  capabilities: {
+    selectable: { hitVolume: 'bbox' },
+    duplicable: true,
+    deletable: true,
+  },
+
+  parametrics: windowParametrics,
+
+  renderer: {
+    kind: 'parametric',
+    module: () => import('./renderer'),
+  },
+  system: {
+    module: () => import('./system'),
+    priority: 3,
+  },
+
+  toolHints: [
+    { key: 'Left click', label: 'Place window on wall' },
+    { key: 'Esc', label: 'Cancel' },
+  ],
+
+  presentation: {
+    label: 'Window',
+    description: 'A window cut into a wall. Animated open/close for opening windows.',
+    icon: { kind: 'iconify', name: 'lucide:rectangle-horizontal' },
+    paletteSection: 'structure',
+    paletteOrder: 60,
+  },
+
+  mcp: {
+    description: 'A window mounted on a wall, with type / dimensions / opening options.',
+  },
+}
diff --git a/packages/nodes/src/window/index.ts b/packages/nodes/src/window/index.ts
new file mode 100644
index 00000000..e05a9db7
--- /dev/null
+++ b/packages/nodes/src/window/index.ts
@@ -0,0 +1,2 @@
+export { windowDefinition } from './definition'
+export { WindowNode } from './schema'
diff --git a/packages/nodes/src/window/parametrics.ts b/packages/nodes/src/window/parametrics.ts
new file mode 100644
index 00000000..a671ab57
--- /dev/null
+++ b/packages/nodes/src/window/parametrics.ts
@@ -0,0 +1,21 @@
+import type { ParametricDescriptor } from '@pascal-app/core'
+import type { WindowNode } from './schema'
+
+/**
+ * Minimal inspector descriptor for window. Like door, the legacy
+ * `<WindowPanel>` has 15+ SliderControls covering sashes, dividers,
+ * sill, frame, opening shape — too elaborate for the auto-inspector
+ * at Stage A. Legacy panel keeps rendering via panel-manager's
+ * `case 'window':`.
+ */
+export const windowParametrics: ParametricDescriptor<WindowNode> = {
+  groups: [
+    {
+      label: 'Dimensions',
+      fields: [
+        { key: 'width', kind: 'number', unit: 'm', min: 0.3, max: 4, step: 0.05 },
+        { key: 'height', kind: 'number', unit: 'm', min: 0.3, max: 4, step: 0.05 },
+      ],
+    },
+  ],
+}
diff --git a/packages/nodes/src/window/renderer.tsx b/packages/nodes/src/window/renderer.tsx
new file mode 100644
index 00000000..9dcb7962
--- /dev/null
+++ b/packages/nodes/src/window/renderer.tsx
@@ -0,0 +1,9 @@
+'use client'
+
+import { WindowRenderer } from '@pascal-app/viewer'
+
+/**
+ * Wrap-export of the legacy `WindowRenderer`. Thin (~36 lines); Phase 5
+ * Stage F inlines it here and deletes the viewer-side file.
+ */
+export default WindowRenderer
diff --git a/packages/nodes/src/window/schema.ts b/packages/nodes/src/window/schema.ts
new file mode 100644
index 00000000..f1f47eaa
--- /dev/null
+++ b/packages/nodes/src/window/schema.ts
@@ -0,0 +1 @@
+export { WindowNode } from '@pascal-app/core'
diff --git a/packages/nodes/src/window/system.tsx b/packages/nodes/src/window/system.tsx
new file mode 100644
index 00000000..58e488bb
--- /dev/null
+++ b/packages/nodes/src/window/system.tsx
@@ -0,0 +1,27 @@
+'use client'
+
+import { WindowAnimationSystem, WindowSystem } from '@pascal-app/viewer'
+
+/**
+ * Registry-driven window system bundle. Same shape as door — two
+ * per-frame systems wrapped together:
+ *
+ *  - **`WindowSystem`** — rebuilds frame / sash / divider / sill /
+ *    muntin geometry. Cascades dirty to parent wall for the cutout.
+ *  - **`WindowAnimationSystem`** — advances sash/panel open state at
+ *    frame priority 2, then marks the window dirty for the geometry
+ *    rebuild at priority 3.
+ *
+ * Both wrapped in `<LegacySystem kind="window">` legacy mounts; with
+ * window registered, those short-circuit and this bundle takes over.
+ */
+const WindowSystems = () => {
+  return (
+    <>
+      <WindowAnimationSystem />
+      <WindowSystem />
+    </>
+  )
+}
+
+export default WindowSystems
diff --git a/packages/viewer/src/index.ts b/packages/viewer/src/index.ts
index 7ea2af6f..72f24ba8 100644
--- a/packages/viewer/src/index.ts
+++ b/packages/viewer/src/index.ts
@@ -8,7 +8,12 @@
 // to duplicate at Stage A. Wrap-exported here, ported into the nodes
 // folder in a later stage.
 export { CeilingRenderer } from './components/renderers/ceiling/ceiling-renderer'
+// Door + window internals for registry-driven door / window definitions.
+// Each kind has a geometry system + animation system to mount via
+// RegisteredSystems when the kind is registry-driven.
+export { DoorRenderer } from './components/renderers/door/door-renderer'
 export { NodeRenderer } from './components/renderers/node-renderer'
+export { WindowRenderer } from './components/renderers/window/window-renderer'
 export { default as Viewer } from './components/viewer'
 export type { HoverStyle, HoverStyles } from './components/viewer/post-processing'
 export {
@@ -38,6 +43,8 @@ export {
 export { mergedOutline } from './lib/merged-outline-node'
 export { default as useViewer } from './store/use-viewer'
 export { CeilingSystem } from './systems/ceiling/ceiling-system'
+export { DoorAnimationSystem } from './systems/door/door-animation-system'
+export { DoorSystem } from './systems/door/door-system'
 // Fence system follows the wall re-export pattern — composed into the
 // registry-driven fence definition's `def.system`. Removed in Phase 6
 // alongside the legacy fence mount point.
@@ -57,3 +64,5 @@ export { getVisibleWallMaterials } from './systems/wall/wall-materials'
 // 800+ lines of CSG / mitering logic during Phase 3. These exports are
 // removed in Phase 6 when the legacy mount points are deleted.
 export { WallSystem } from './systems/wall/wall-system'
+export { WindowAnimationSystem } from './systems/window/window-animation-system'
+export { WindowSystem } from './systems/window/window-system'