This article proposes applying semantic web and artificial intelligence planning techniques to a web services composition model dealing with problems of ambiguity in web service Ingredients description and handling incomplete web information.The model uses an OWL-S services and implements a planning technique which handles open world semantics in its reasoning process to resolve these problems.This resulted in a web services composition system incorporating a module for interpreting OWL-S services and converting them 2 Way 8" into a planning problem in PDDL (a planning module handling incomplete information) and an execution service module concurrently interacting with the planner for executing each composition plan service.