  We consider an extension of the MSSM with an added vectorlike top partner.
Our aim is to revisit to what extent such an extension can raise the Higgs
boson mass through radiative corrections and help ameliorate the MSSM hierarchy
problem, and to specify what experimental probes at the LHC will find or
exclude this possibility during the high-luminosity phase. Direct detection,
precision electroweak and precision Higgs analyses are all commissioned to this
end. To achieve the $ 125 \, \textrm{GeV} \ $ Higgs boson mass, we find that
superpartner masses can be reduced by a factor of more than three in this
scenario compared to the MSSM without the extra vectorlike top quark, and that
during the high-luminosity phase of the LHC precision Higgs analysis is
expected to become the most powerful experimental probe of the scenario.
