We present an agent-based and context-oriented approach for Web services composition. A Web service is an accessible application that other applications and humans can discover and trigger to satisfy various needs. Due to the complexity of Web services composition, we consider two concepts to reduce this complexity: Software agent and context. A software agent is an autonomous entity that acts on behalf of users, whereas context is any information relevant to characterize a situation. During composition, software agents engage conversations with their peers to agree on the Web services that will participate in the composition.