Mimir includes a ruler component, which is responsibile to evaluate Prometheus recording and alerting rules. It also exposes a set of APIs to configure the rule groups.
Mimir is released with a CLI tool called "mimirtool" which, among other things, allow you to configure the rule groups (under the hood, it calls the Mimir API). Mimirtool documentation is here:
https://grafana.com/docs/mimir/latest/operators-guide/tools/...