  We develop a symmetry-based low-energy theory for monolayer $\mathrm{WTe}_2$
in its 1T$^{\prime}$ phase, which includes eight bands (four orbitals, two
spins). This model reduces to the conventional four-band spin-degenerate Dirac
model near the Dirac points of the material. We show that measurements of the
spin susceptibility, and of the magnitude and time dependence of the anomalous
Hall conductivity induced by injected or equilibrium spin polarization can be
used to determine the magnitude and form of the spin-orbit coupling
Hamiltonian, as well as the dimensionless tilt of the Dirac bands.
