This volume is a computational and mathematical companion to the article "Information-Theoretic and Operational Measures of Quantum Contextuality". Rather than introducing new conceptual results, it provides complete derivations, independent cross-validations, and reproducible numerical implementations of every key result in the main article. Each quantity is established by two independent routes ---a direct matrix method using spin-1 operators, eigenvalue decompositions, and trace operations, and a geometric method based on the Majorana–Stellar representation on the Bloch–Poincaré sphere--- ensuring robustness against basis choices, degeneracies, and numerical artefacts. The treatment covers the KCBS geometry and observables, the mutual information energy, the operational contextuality measure D(G, ρ̂), the Majorana–Stellar formulation, and the associated uncertainty-optimization results, together with the accompanying Python reference implementation. It is intended for researchers and graduate students in quantum foundations, quantum information theory, and mathematical physics, assuming a working familiarity with finite-dimensional quantum mechanics. Published open access by Mersin University Press under a Creative Commons Attribution 4.0 International (CC BY 4.0) license.