diff --git a/packages/extension-gapcursor/src/gapcursor.ts b/packages/extension-gapcursor/src/gapcursor.ts
index 73bf9325..4257c5cf 100644
--- a/packages/extension-gapcursor/src/gapcursor.ts
+++ b/packages/extension-gapcursor/src/gapcursor.ts
@@ -6,7 +6,10 @@ declare module '@tiptap/core' {
     /**
      * Allow gap cursor
      */
-    allowGapCursor?: boolean | ((this: { options: Options }) => boolean),
+    allowGapCursor?:
+      | boolean
+      | null
+      | ((this: { options: Options }) => boolean | null),
   }
 }