To extend the product environment, you should be familiar with standard Eclipse extension mechanisms. You can also package extensions as reusable assets and then reuse them through a Reusable Java™ Asset Specification (RAS) server. Another way to extend the product environment is to create pluglets. Pluglets are special projects within the workspace that you can use to create standalone Java™ applications that can access and modify a UML model.
Because the product is based on many components of the Eclipse open source framework, all those application programming interfaces (APIs) are available to you. For example, you can use the UML2 APIs to manipulate models, Eclipse Graphical Modeling Framework (GMF) APIs to manipulate diagrams, and so on. In addition to these APIs, the Rational® Software Architect platform provides additional APIs with specific capabilities for capsule-based modeling, as well as capabilities that help you manipulate model elements. You can also easily add new menus.
The product has several UML profiles, and you can also create and use new profiles to further enhance the modeling experience. The product provides tools to create a profile and produce code so that the profile’s elements appear in the diagram toolset and in menus. You can also adapt the generated code to refine its capabilities. For more details, see “Extending the Rational modeling environment.”
Because it is based on Eclipse, configuration management (CM) providers can integrate with the product platform, and can reuse the model comparison and merging tools by connecting to the correct Eclipse service.
The product transformation that generates C++ code from models is also extensible. For more details, see “Extending transformations.”
You can extend both the validation and analysis tools in the product. You typically extend the validation tool by providing new constraints on models. By default, a set of rules is provided to support the base UML capabilities.

