diff --git a/packages/content-format/src/nodes/HeadingNode.ts b/packages/content-format/src/nodes/HeadingNode.ts
index 216eec1..b734250 100644
--- a/packages/content-format/src/nodes/HeadingNode.ts
+++ b/packages/content-format/src/nodes/HeadingNode.ts
@@ -2,7 +2,7 @@ import { ComposedElement } from '../ComposedElement';
 import type { Node } from '../Node';
 
 export interface HeadingNode<Child extends Node> extends ComposedElement<`${HeadingNode.Type}`, Child> {
-    role?: HeadingNode.Role;
+    role?: `${HeadingNode.Role}`;
 }
 
 export namespace HeadingNode {