I haven’t found anything well-documented for controlling SmartThing items using OpenHAB while I had found some well-documented tutorials for connecting Philips Hue and Insteon to OpenHAB. I don’t even see any binding for it in the “addons” folder in /opt/openhab/addon and I am using version 1.8.1 of OpenHAB. So there is no way to control SmartThings items using OpenHAB like controlling its motion sensor or dimmer switch or IDK presence sensor?
Just run really fast from SmartThings… that’s your best option. I did that a while ago.
But, if you insist, there’s nothing direct that I know of. You will probably have to create a custom ST app with unique rest endpoints that openhab could reach via http addon. You’d have to manually “link” the two and write down the generated auth key from ST. There’s no easy solution. I had originally thought about similar to control my locks in ST - but they are now close with zwave binding. Plus, it’s just been shown how to hack ST.