The Port Tool is used to define ports that can be used as part of object symbols, and to which roles will attach. Ports allow additional semantics or constraints on how objects can be connected. For example, we can set a requirement for the Family Tree diagram that all parental relationships must connect to the top edge of the Person symbol and all child relationships to its bottom edge.

Ports can also have their own properties, which are used primarily to set port-related constraints (see Section 2.5.5). Ports do not have symbols or icons of their own, but they are visualized by Connectables in object type symbols (for more information about Connectables, see Section 3.2.9).