With the increase of resources and processing power on the Smart Cards, in recent days, their applicability has moved from a domain specific application to a more generic one. Multi-Application Frameworks, designed to host multiple applications on a card, also aim at increasing the interoperability between different vendors and their applications. This paper proposes a new model named XML Agent, which significantly enhances the inter-operability of the smart card applications. The XML Agent becomes an interface through which the external world can interact with the on-card applications. The XML Agent passes the commands and data to the appropriate application as per its requirements. This model will also facilitate the programmer in developing off-card applications, with minimal information about the on-card applications.