The argocd.argoproj.io/managed-by-url annotation allows an Application resource to specify which Argo CD instance manages it. This is useful when you have multiple Argo CD instances and need application links in the UI to point to the correct managing instance. Use Case: When using multiple Argo CD instances with the app-of-apps pattern: A primary Argo CD instance creates a parent Application That parent Application deploys child Applications managed by a secondary Argo CD instance Without the annotation, clicking on child Applications in the primary instance's UI tries to open them in the primary instance (incorrect) The child Applications should open in the secondary instance instead The managed-by-url annotation ensures application links redirect to the correct Argo CD instance.