  We analyse the efficiency of future large scale structure surveys to unveil
the presence of scale dependent features in the primordial spectrum --resulting
from cosmic inflation-- imprinted in the distribution of galaxies. Features may
appear as a consequence of non-trivial dynamics during cosmic inflation, in
which one or more background quantities experienced small but rapid deviations
from their characteristic slow-roll evolution. We consider two families of
features: localized features and oscillatory extended features. To characterise
them we employ various possible templates parametrising their scale dependence
and provide forecasts on the constraints on these parametrisations for LSST
like surveys. We perform a Fisher matrix analysis for three observables: cosmic
microwave background (CMB), galaxy clustering and weak lensing. We find that
the combined data set of these observables will be able to limit the presence
of features down to levels that are more restrictive than current constraints
coming from CMB observations only. In particular, we address the possibility of
gaining information on currently known deviations from scale invariance
inferred from CMB data, such as the feature appearing at the $\ell \sim 20$
multipole (which is the main contribution to the low-$\ell$ deficit) and a
potential feature appearing at $\ell \sim 800$.
