The literature on blockchain for AEC often has limited discussion on the design of the blockchain Oracle, the entity that ensures trusted information input from the real world. This work aims to illuminate an often unaddressed topic of how to best design Oracles for application to the AEC industry. To answer this, the paper reviews the stateof-the-art of existing Oracle taxonomies, literature on blockchain for AEC that implement Oracles, and proposes Oracle design dimensions to frame future blockchain work. The work can help researchers and practitioners to think about relevant dimensions when designing and discussing Oracles for AEC use cases.