  We present science cases and instrument design considerations for the BIFROST
instrument that will open the short-wavelength (Y/J/H-band), high spectral
dispersion (up to R=25,000) window for the VLT Interferometer. BIFROST will be
part of the Asgard Suite of instruments and unlock powerful venues for studying
accretion & mass-loss processes at the early/late stages of stellar evolution,
for detecting accreting protoplanets around young stars, and for probing the
spin-orbit alignment in directly-imaged planetary systems and multiple star
systems. Our survey on GAIA binaries aims to provide masses and precision ages
for a thousand stars, providing a legacy data set for improving stellar
evolutionary models as well as for Galactic Archaeology. BIFROST will enable
off-axis spectroscopy of exoplanets in the 0.025-1" separation range, enabling
high-SNR, high spectral resolution follow-up of exoplanets detected with ELT
and JWST. We give an update on the status of the project, outline our key
technology choices, and discuss synergies with other instruments in the
proposed Asgard Suite of instruments.
