Based on the distinctive distribution of gender/number features and definiteness/case features on attributive and predicative adjectives, I argue that gender and number features are agreement features that are manipulated in the syntax through Bidirectional Agree (Baker 2008; Baier 2015) while definiteness and case features are concord features shared through Morphological Feature Copying and AGR node insertion at PF (Norris 2014). In further discussion of case features, I show that case features may be valued either at PF for attributive adjectives, like definiteness features, or in the syntax via case assignment for predicative adjectives. As such, the analysis predicts the distribution of gender, number, definiteness, and case features on both predicative and attributive adjectives in Modern Standard Arabic. In doing so, it provides novel evidence in support for the division of agreement and concord features in language derivation.