  We determined the full orbital architecture and true mass of the recently
Doppler-detected long-period giant planet GJ 463 b using the HIPPARCOS-Gaia
proper motion anomaly in combination with the available radial velocities,
constraints from the knowledge of the spectroscopic orbital parameters, and
supplementary information from a sensitivity analysis of Gaia Data Release 3
astrometry. We determined an orbital inclination $i_b=152^{+2}_{-3}$ deg (for a
prograde orbit) and a mass ratio $q=0.0070\pm0.0007$, corresponding to a true
mass of the companion $M_b=3.6\pm0.4$ M$_\mathrm{Jup}$. True mass
determinations for a super-Jupiter companion at intermediate orbital
separations beyond the snow line around low-mass stars ($M_\star\leq 0.5$
M$_\odot$) are a rare occurrence. Its existence is possibly explained in the
context of disk-instability models of planet formation.
