  We present the DMSimpt model implementation in FeynRules, which aims to offer
a unique general framework allowing for all simulations relevant for simplified
$t$-channel dark matter models at colliders and for the complementary cosmology
calculations. We describe how to match next-to-leading-order QCD fixed-order
calculations with parton showers to derive robust bounds and predictions in the
context of LHC dark matter searches, and moreover validate two model
restrictions (relevant for Dirac and Majorana fermionic dark matter
respectively) to exemplify how to evaluate dark matter observables to constrain
the model parameter space. More importantly, we emphasise how to achieve these
results by using a combination of publicly available automated tools, and
discuss how dark matter predictions are sensitive to the model file and
software setup. All files, together with illustrative Mathematica notebooks,
are available from the URL http://feynrules.irmp.ucl.ac.be/wiki/DMsimpt.
