Abstract. One of the major advantages of component-based software engineering is the ability for developers to reuse and assemble software entities to build complex software. Whereas decomposition of software into components has been and is largely addressed for what concerns the business (functional) part of applications, this is not yet the case for what concerns their documentation (non-functional) part. In this paper, we propose a new and original solution to express component-based software non-functional documentation, and we will focus more especially on architecture constraints, which formalize parts of architecture decisions, as executable, customizable, reusable and composable building blocks represented by components. Component-based applications using business and constraint components can be modeled with CLACS, a dedicated ADL which is also introduced in the paper. Architecture constraints can be executed at design-time within CLACS. CLACS is implemented as a plugin in the Eclipse IDE.