To add custom fields to Content Fragment properties, don’t modify /libs directly - instead, overlay the editor form under /apps/dam/content/schemaeditors/forms/contentfragment and make sure your custom field is properly defined under items/tabs/items/tab1/items/col1/items with correct sling:resourceType, name, and fieldLabel. The error you're getting (Unable to create node at) usually means you're missing permissions or trying to save a property where the path doesn't allow it (like adding nested nodes to a property). Also, ensure your field is not trying to create child nodes dynamically unless it's a multifield or complex widget. If it’s still not showing up, double-check that the form is properly overlaid, your node structure is valid, and you're editing the Content Fragment Model editor UI, not the asset metadata schema. If asked, the exact solution is: overlay the content fragment editor under /apps, define your custom field under tab1 -> col1, ensure it's not using a node structure that creates child items unless supported, and never modify /libs directly.
