A computer implemented method of reviewing applications for delivery via an application delivery server, the method comprising: identifying, for an application submitted by an application developer, a messaging object configured with an action by the application developer, wherein the application with the messaging object causes the application to fulfill the action or perform an action, and wherein the action comprises performing a function or providing a content item; determining a first classification score based on historical execution of the action of the messaging object provided by the application developer; generating a machine generated action for the application based on metadata associated with the application by mapping the metadata to a predetermined list of actions; determining a second classification score based on a comparison of the action of the messaging object provided by the application developer with the machine generated action; selecting, via a matching program, a second application that matches the application, the second application already having passed the review process; determining a third classification score based on a comparison of an action approved for the second application with the action of the messaging object provided by the application developer; determining (210, 218, 226) if a classification failure is present based on the first classification score, the second classification score and the third classification score; updating, responsive to determining a classification failure is present, a delivery control parameter based on the first classification score, the second classification score and the third classification score; and controlling, responsive to the delivery control parameter updated by the data processing system, delivery of the application by the application delivery server, wherein controlling delivery of the application comprises preventing delivery of the application or disabling the action of the messaging object for execution via the application. identifying, for an application submitted by an application developer, a messaging object configured with an action by the application developer, wherein the application with the messaging object causes the application to fulfill the action or perform an action, and wherein the action comprises performing a function or providing a content item; determining a first classification score based on historical execution of the action of the messaging object provided by the application developer; generating a machine generated action for the application based on metadata associated with the application by mapping the metadata to a predetermined list of actions; determining a second classification score based on a comparison of the action of the messaging object provided by the application developer with the machine generated action; selecting, via a matching program, a second application that matches the application, the second application already having passed the review process; determining a third classification score based on a comparison of an action approved for the second application with the action of the messaging object provided by the application developer; determining (210, 218, 226) if a classification failure is present based on the first classification score, the second classification score and the third classification score; updating, responsive to determining a classification failure is present, a delivery control parameter based on the first classification score, the second classification score and the third classification score; and controlling, responsive to the delivery control parameter updated by the data processing system, delivery of the application by the application delivery server, wherein controlling delivery of the application comprises preventing delivery of the application or disabling the action of the messaging object for execution via the application.