  We derive the scalar-tensor Hamiltonian constraint to all orders of momenta
when the canonical constraint algebra is deformed by a phase space function as
predicted by some studies into loop quantum cosmology. We find that the momenta
and spatial derivatives from gravity and matter fields must combine in a very
specific form to maintain a deformed general covariance. This suggests that the
deformation should be equally caused by matter field derivatives as it is by
gravitational curvature. We demonstrate the cosmological consequences of a
variety of deformation functions. Some cause a big bounce at high energy
densities and others cause a sudden singularity.
