diff --git a/packages/boxel-ui/addon/src/components/drag-and-drop/index.gts b/packages/boxel-ui/addon/src/components/drag-and-drop/index.gts
index f8f8ea7da7..c5fc5511c8 100644
--- a/packages/boxel-ui/addon/src/components/drag-and-drop/index.gts
+++ b/packages/boxel-ui/addon/src/components/drag-and-drop/index.gts
@@ -6,6 +6,11 @@ import Component from '@glimmer/component';
 import { tracked } from '@glimmer/tracking';
 
 import { and, eq } from '../../helpers/truth-helpers.ts';
+import type {
+  DndDraggableItemModifier,
+  DndDropTargetModifier,
+  DndSortableItemModifier,
+} from '../../types/drag-and-drop.ts';
 
 const isFastBoot = typeof (globalThis as any).FastBoot !== 'undefined';
 
@@ -48,13 +53,16 @@ export default class DndKanbanBoard extends Component<
   DndKanbanBoardSignature<DndColumn>
 > {
   @tracked areModifiersLoaded = false;
-  @tracked DndDraggableItemModifier: any = null;
-  @tracked DndDropTargetModifier: any = null;
-  @tracked DndSortableItemModifier: any = null;
-  @tracked insertAfter: any;
-  @tracked insertAt: any;
-  @tracked insertBefore: any;
-  @tracked removeItem: any;
+  @tracked DndDraggableItemModifier: DndDraggableItemModifier | undefined;
+  @tracked DndDropTargetModifier: DndDropTargetModifier | undefined;
+  @tracked DndSortableItemModifier: DndSortableItemModifier | undefined;
+  @tracked insertAfter: <T>(array: T[], index: number, element: T) => T[] =
+    undefined as any;
+  @tracked insertAt: <T>(array: T[], index: number, element: T) => T[] =
+    undefined as any;
+  @tracked insertBefore: <T>(array: T[], index: number, element: T) => T[] =
+    undefined as any;
+  @tracked removeItem: <T>(array: T[], item: T) => T[] = undefined as any;
   @tracked draggedCard: DndItem | null = null;
 
   constructor(owner: unknown, args: DndKanbanBoardArgs<DndColumn>) {
@@ -70,25 +78,22 @@ export default class DndKanbanBoard extends Component<
   // See: https://github.com/alvarocastro/ember-draggable-modifiers/issues/1 and https://github.com/cardstack/boxel/pull/1683#discussion_r1803979937
   async loadModifiers() {
     // @ts-expect-error Dynamic imports are only supported when the '--module' flag is set to 'es2020', 'es2022', 'esnext', 'commonjs', 'amd', 'system', 'umd', 'node16', or 'nodenext'
-    const DndDraggableItemModifier = await import(
+    const DndDraggableItemModifier: DndDraggableItemModifier = await import(
       'ember-draggable-modifiers/modifiers/draggable-item'
     );
 
     // @ts-expect-error Dynamic imports are only supported when the '--module' flag is set to 'es2020', 'es2022', 'esnext', 'commonjs', 'amd', 'system', 'umd', 'node16', or 'nodenext'
-    const DndDropTargetModifier = await import(
+    const DndDropTargetModifier: DndDropTargetModifier = await import(
       'ember-draggable-modifiers/modifiers/drop-target'
     );
 
     // @ts-expect-error Dynamic imports are only supported when the '--module' flag is set to 'es2020', 'es2022', 'esnext', 'commonjs', 'amd', 'system', 'umd', 'node16', or 'nodenext'
-    const DndSortableItemModifier = await import(
+    const DndSortableItemModifier: DndSortableItemModifier = await import(
       'ember-draggable-modifiers/modifiers/sortable-item'
     );
     // @ts-expect-error Dynamic imports are only supported when the '--module' flag is set to 'es2020', 'es2022', 'esnext', 'commonjs', 'amd', 'system', 'umd', 'node16', or 'nodenext'
     const arrayUtils = await import('ember-draggable-modifiers/utils/array');
 
-    this.DndDraggableItemModifier = DndDraggableItemModifier.default;
-    this.DndDropTargetModifier = DndDropTargetModifier.default;
-    this.DndSortableItemModifier = DndSortableItemModifier.default;
     this.insertAfter = arrayUtils.insertAfter;
     this.insertAt = arrayUtils.insertAt;
     this.insertBefore = arrayUtils.insertBefore;
diff --git a/packages/boxel-ui/addon/src/types/drag-and-drop.ts b/packages/boxel-ui/addon/src/types/drag-and-drop.ts
new file mode 100644
index 0000000000..0fc10e3ee2
--- /dev/null
+++ b/packages/boxel-ui/addon/src/types/drag-and-drop.ts
@@ -0,0 +1,71 @@
+import Modifier from 'ember-modifier';
+
+export interface DndDraggableItemSignature {
+  Args: {
+    Named: {
+      data?: any;
+      disabled?: boolean;
+      dragHandleElement?: string;
+      group?: string;
+      isDraggingClass?: string;
+      onDragEnd?: (event: DragEvent) => void;
+      onDragStart?: (event: DragEvent) => void;
+      onDrop?: (event: { destination: unknown; source: unknown }) => void;
+    };
+    Positional: [];
+  };
+}
+
+export interface DndDropTargetSignature {
+  Args: {
+    Named: {
+      accepts?: string[];
+      allowDropOnChildren?: boolean;
+      allowDropOnItself?: boolean;
+      allowedEdges?: ('top' | 'bottom' | 'left' | 'right')[];
+      canDrop?: (event: DragEvent) => boolean;
+      data?: any;
+      direction?: 'horizontal' | 'vertical';
+      disabled?: boolean;
+      group?: string;
+      isOnTargetClass?: string;
+      onDragEnter?: (event: DragEvent) => void;
+      onDragLeave?: (event: DragEvent) => void;
+      onDrop?: (event: DragEvent, item: any) => void;
+      onHover?: (event: DragEvent) => void;
+    };
+    Positional: [];
+  };
+}
+
+export interface DndSortableItemSignature {
+  Args: {
+    Named: {
+      accepts?: string[];
+      allowDropOnChildren?: boolean;
+      allowDropOnItself?: boolean;
+      allowedEdges?: ('top' | 'bottom' | 'left' | 'right')[];
+      canDrop?: (event: DragEvent) => boolean;
+      data?: any;
+      direction?: 'horizontal' | 'vertical';
+      disabled?: boolean;
+      disabledDrag?: boolean;
+      disabledDrop?: boolean;
+      dragHandleElement?: string;
+      group?: string;
+      isDraggingClass?: string;
+      isOnTargetClass?: string;
+      onDragEnd?: (event: DragEvent) => void;
+      onDragEnter?: (event: DragEvent) => void;
+      onDragLeave?: (event: DragEvent) => void;
+      onDragStart?: (event: DragEvent) => void;
+      onDrop?: (event: DragEvent, item: any) => void;
+      onHover?: (event: DragEvent) => void;
+    };
+    Positional: [];
+  };
+}
+
+export type DndDraggableItemModifier = Modifier<DndDraggableItemSignature>;
+export type DndDropTargetModifier = Modifier<DndDropTargetSignature>;
+export type DndSortableItemModifier = Modifier<DndSortableItemSignature>;
diff --git a/packages/experiments-realm/todo-app.gts b/packages/experiments-realm/todo-app.gts
new file mode 100644
index 0000000000..65b237258f
--- /dev/null
+++ b/packages/experiments-realm/todo-app.gts
@@ -0,0 +1,11 @@
+import {
+  field,
+  CardDef,
+  linksToMany,
+} from 'https://cardstack.com/base/card-api';
+import { Todo } from './todo';
+
+export class TodoApp extends CardDef {
+  static displayName = 'Todo App';
+  @field todos = linksToMany(() => Todo);
+}