An artifact is a tangible work product that is consumed, produced, or modified by tasks. Artifacts may be composed of other artifacts. For example, a model artifact can be composed of model elements, which are also artifacts.
Roles use artifacts to perform tasks and to produce other artifacts. Each artifact is the responsibility of a single role, making responsibility easy to identify and understand, and promoting the idea that every piece of information produced in a method requires the appropriate set of skills. Even though only one role is responsible for an artifact, other roles may use the artifacts.