I used the checkmk built-in Swagger UI and also ReDoc but on rulesets there are no POST requests available. I can find POST only on rules but there is no “Assignment of hosts to host groups” possible like in the checkmk webfrontend (if you create a hostgroup rule manually).
Thanks
Martin
Edit: I have Checkmk Raw Edition 2.2.0b5, maybe this is only available on a higher tier level?