I created a python script for a toolbox and I am wondering about the fact that CreateFeatureclass\_management doesn't add the feature-class as layer in the actual dataframe. This does not happen in the environment of a toolbox, but if I create a feature-class in the python window of ArcMap it creates the wanted layer.

I already tried MakeFeatureLayer\_management followed by AddLayer, with no result.

What I am doing wrong?