I guess you are looking for a way to launch the XML Schema Wizard add-in that Studio offers.

Try adapting the advice at https://docs.intersystems.com/components/csp/docbook/DocBook.UI.Page.cls... for adding a custom entry to the Server Actions menu. In this case the entry in the "links" object within "objectscript.conn" should be:

"Open XML Schema Wizard": "${serverUrl}/isc/studio/templates/%25ZEN.Template.AddInWizard.XMLSchemaWizard.cls?$NAMESPACE=${ns}"