This paper argues that a significant focus in computational organic chemistry, alongside the construction and deployment of models, is the “deconstruction” of computational models. This practice has arisen in response to difficulties and controversies resulting from the use of plural methods and computational models to study organic reaction mechanisms. Diagnostic controllability is the capacity of cognitive agents to gain epistemic access to grey-boxed computational models, to identify and explain the impact of specific idealizations on results, and to demonstrate the applicability (...) of computational methods to target systems. (shrink)