  The Trappist-1 planets provide a unique opportunity to test the current
understanding of rocky planet evolution. The James Webb Space Telescope is
expected to characterize the atmospheres of these planets, potentially
detecting CO$_2$, CO, H$_2$O, CH$_4$, or abiotic O$_2$ from water
photodissociation and subsequent hydrogen escape. Here, we apply a coupled
atmosphere-interior evolution model to the Trappist-1 planets to anticipate
their modern atmospheres. This model, which has previously been validated for
Earth and Venus, connects magma ocean crystallization to temperate geochemical
cycling. Mantle convection, magmatic outgassing, atmospheric escape, crustal
oxidation, a radiative-convective climate model, and deep volatile cycling are
explicitly coupled to anticipate bulk atmospheres and planetary redox evolution
over 8 Gyr. By adopting a Monte Carlo approach that samples a broad range of
initial conditions and unknown parameters, we make some tentative predictions
about current Trappist-1 atmospheres. We find that anoxic atmospheres are
probable, but not guaranteed, for the outer planets; oxygen produced via
hydrogen loss during the pre-main sequence is typically consumed by crustal
sinks. In contrast, oxygen accumulation on the inner planets occurs in around
half of all models runs. Complete atmospheric erosion is possible but not
assured for the inner planets (occurs in 20%-50% of model runs), whereas the
outer planets retain significant surface volatiles in virtually all model
simulations. For all planets that retain substantial atmospheres,
CO$_2$-dominated or CO$_2$-O$_2$ atmospheres are expected; water vapor is
unlikely to be a detectable atmospheric constituent in most cases. There are
necessarily many caveats to these predictions, but the ways in which they
misalign with upcoming observations will highlight gaps in terrestrial planet
knowledge.
