\begin{abstract} Policy and industry discourse often reduce artificial intelligence (AI) to machine learning framed as “supervised, unsupervised, or reinforcement learning.” This triad omits long-standing AI traditions (symbolic expert systems, search \& planning, probabilistic inference, control/estimation, and evolutionary/collective computation). We formalize the \emph{Operational-Premise Taxonomy}~(OPT), classifying AI by its dominant computational mechanism: \Lrn, \Evo, \Sym, \Prb, \Sch, \Ctl, and \Swm. For each class we provide core mathematical operators, link them to canonical biological mechanisms, and survey hybrid compositions. We argue that OPT yields a principled, biologically grounded, and governance-usable taxonomy that avoids category errors inherent in training-signal–based labels, while remaining compact and readable with a short, compositional naming code. We propose a grammar for decription, evaluation process methods, and argue for the utility of OPT in both post-hoc classification of systems and as a design-time adjunct that aids in software development and lifecycle risk management processes. OPT can serve as an adjunct and complement to existing frameworks of software risk management given its basis in the operational mechanisms of the software rather than more superficial characteristics commonly used. \end{abstract}