Is there any way in Houdini to add comments to parameters? Eg I’d like to right click a parameter and comment things like ‘use values between range … to keep this stable’.

Thank you

If it's a hda you are making you can add tooltips when you mouse over the parameter. You can find out more about this here: https://www.sidefx.com/docs/houdini/help/nodes.html#parameters-section [www.sidefx.com]
You can also do this if you are editing the parameter interface on any node via right click parameter>edit parameter interface
The help field is at the bottom when you select a parameter