  This document summarizes how far the Nancy Grace Roman Space Telescope
Coronagraph Instrument (Roman CGI) will go toward demonstrating high-contrast
imaging and spectroscopic requirements for potential future exoplanet direct
imaging missions, illustrated by the HabEx and LUVOIR concepts. The assessment
is made for two levels of assumed CGI performance: (i) current best estimate
(CBE) as of August 2020, based on laboratory results and realistic end-to-end
simulations with JPL-standard Model Uncertainty Factors (MUFs); (ii) CGI design
specifications inherited from Phase B requirements. We find that the predicted
performance (CBE) of many CGI subsystems compares favorably with the needs of
future missions, despite providing more modest point source detection limits
than future missions. This is essentially due to the challenging pupil of the
Roman Space Telescope; this pupil pushes the coronagraph masks sensitivities to
misalignments to be commensurate with future missions. In particular, CGI will
demonstrate active low-order wavefront control and photon counting capabilities
at levels of performance either higher than, or comparable to, the needs of
future missions.
