SMEFT predictions for $gg\to hh$ at full NLO QCD and truncation uncertainties

We present a calculation of the NLO QCD corrections for Higgs-boson pair production in gluon fusion including effects of anomalous couplings within Standard Model Effective Field Theory (SMEFT). We study effects of different truncation options of the EFT expansion in $1\mathrm{/}\mathrm{\Lambda }$ and of double operator insertions, both at total cross-section level as well as for the distribution of the invariant mass of the Higgs-boson pair, at $\sqrt{s}=13$ TeV. The NLO corrections are implemented in the generator \texttt{ggHH_SMEFT} in the $\mathtt{\text{Powheg-Box-V2}}$ framework.