We present a strategy to extend lattice calculations of inclusive hadronic $\tau$ decays from isosymmetric QCD to QCD+QED.
The inclusive decay rate can be related to suitable Euclidean correlation functions, allowing for a first-principles evaluation of electromagnetic and isospin-breaking effects.
Within the RM123 framework, radiative corrections are decomposed into leptonic, factorizable and non-factorizable contributions.
We report preliminary results for the leptonic and factorizable terms in the electro-quenched approximation and discuss the remaining steps towards a complete calculation.
This programme aims at a first-principles determination of inclusive $\tau$ decay rates with direct implications for the extraction of the CKM matrix element $|V_{us}|$.

