We present $\texttt{NPointFunctions}$, a package to incorporate desired amplitudes and observables for an arbitrary BSM model in $\texttt{FlexibleSUSY}$. The package relies on the $\texttt{SARAH}$-generated output used with $\texttt{FeynArts}/\texttt{FormCalc}$, embedded in an appropriate way, thus allowing calculations up to one-loop level. The resulting tool is an extension to $\texttt{FlexibleSUSY}$, a generator of spectrum generator programs. $\texttt{NPointFunctions}$ was designed to be customizable, modular and extensible with additional process- or amplitude- dependent contributions. We explain, how these goals are achieved, and discuss modifications to the default $\texttt{FlexibleSUSY}$ workflow.