That's a fair call - a modelling aid would work well. There is a large thread about addressing modelling in Houdini. It may be worth adding it there too.

https://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=31040 [sidefx.com]

I agree with OneBigTree

his request has nothing to do with modeling
it's very useful to have correct shading in the viewport, the only thing he is requesting is to be able to have Angle Cusp setting on object that will cusp viewport vertex normals (and I would suggest automatic render ones as well) when no custom point or vertex N attribute exist

so for now viewport and mantra create automatic N if there is no such attribute and this is handy as you don't need to recompute N on model after each operation
so it's just logical if you are using Angle Cusping as it's quite standard to have this as automatic postprocess on the model handled in Viewport and Render, but really only in case when no custom N exist on object

the Cusp Angle setting can live on Object/Geometry tab, right next to Automatically Compute Normals

I'd like to see this happen as appending Facet or Vertex SOP every time to see correct shading is a little tiring

I think switching to flat shaded is helping to visually “please” myself during big part of modeling stages. When I use smooth shaded, I do it only in conjunction with wires, so It is more like a “debbuging” mode for me.

Adding cusp angle as viewport mode is still going to be pretty good feature tho