Abstract
Web Services (WS) are software components accessible over the Internet through a well-defined set of standards. When consumers invoke a service, they expect to receive a valid response. However, the problem is to determine the structure of a valid request [21]. WS specifications are used to solve this problem since they are considered the primary piece of information for building service requests. Unfortunately, existing specifications do not provide enough support for this type information (e.g., WSDL) or there is little support on the client side (e.g., OWL-S). In this paper we address this issue by implementing a technique to reduce the number of faulty requests. We specifically propose an approach for extending WSDL with service input parameters rules that help consumers and integrators to verify their calls on the client side.