ArchiMate is a graphical language and was developed for IT-architects who want to visualize ideas about the business, the application landscape, the infrastructure, and the strategic concerns of enterprises. Architects can store their models in what we call a repository (i.e. a mechanism to store models).
A problem arises when a repository contains many models. Oversight is lost, models get incomplete, and inconsistencies occur. To a certain extent ArchiMate helps to prevent this by sharing objects between models. But organization-specific constaints cannot and may not be enforced by a generic tool.
ArchiChecker is a tool that lets architects formulate and check organization-specific constaints on their ArchiMate repository.