  We describe new efforts to model radio active galactic nuclei (AGN) in a
cosmological context using the SAGE semi-analytic galaxy model. Our new method
tracks the physical properties of radio jets in massive galaxies, including the
evolution of radio lobes and their impact on the surrounding gas. This model
also self consistently follows the gas cooling-heating cycle that significantly
shapes star formation and the life and death of many galaxy types. Adding jet
physics to SAGE adds new physical properties to the model output, which in turn
allows us to make more detailed predictions for the radio AGN population. After
calibrating the model to a set of core observations we analyse predictions for
jet power, radio cocoon size, radio luminosity, and stellar mass. We find that
the model is able to match the stellar mass--radio luminosity relation at
$z\sim0$, and the radio luminosity function out to $z\sim1$. This updated model
will make possible the construction of customised AGN-focused mock survey
catalogues to be used for large-scale observing programs.
