Design Science Research (DSR) in Information Systems intends to extend the design knowledge base, i.e. the cumulative amount of prescriptive guidance that comprises valid solution design knowledge and solution entities. DSR projects contribute to this knowledge base by adding project design knowledge (PDK), i.e. utility statements linking the solution space with problem space. While PDK is constantly created in different forms (e.g. methods, models, and design principles), there is no common agreement on how PDK should be conceptually structured in artefact-agnostic form, i.e. which components and relations are essential and what general guidelines are relevant for its development, validation, and evolution. We propose a conceptualization of PDK architecture that comprises ten fundamental concepts, three types of statements, three types of relationships, and guidelines for four different design modes. The proposed PDK architecture provides support for navigating through complex artefact creation activities and for comparing different artefact-specific forms of PDK. Yet, it recognizes the diversity of DSR approaches and settings. A DSR study is used to demonstrate the proposal, also allowing to demonstrate a novel validation technique. Evaluative evidence of the proposal’s utility is presented based on interviews with authors of well-published DSR methodology contributions.