  We examine zero-form charges in Vasiliev's four-dimensional bosonic higher
spin gravities. These are classical observables given by integrals over
noncommutative twistor space of adjoint combinations of the zero-form master
fields, including insertions of delta functions in the deformed oscillators
serving as gauge invariant regulators. The regularized charges admit
perturbative expansions in terms of multi-linear functionals in the Weyl
zero-form, which are Bose symmetric and higher spin invariant by construction,
and that can be interpreted as basic building blocks for higher spin gravity
amplitudes. We compute two- and three-point functions by attaching external
legs given by unfolded bulk-to-boundary propagators, and identify the result
with the two- and three-current correlation functions in theories of free
conformal scalars and fermions in three dimensions. Modulo assumptions on the
structure of the sub-leading corrections, and relying on the generalized
Hamiltonian off-shell formulation, we are thus led to propose an expression for
the free energy as a sum of suitably normalized zero-form charges
