instead of having a hardcoded list of simple checks in the item key helper, frontend could query the server, which would return a json of all currently supported simple checks. it would allow displaying the checks, implemented as loadable modules.
this should be easier to do than agents, as querying remote agents if often impossible. it would result in a requirement for the server to be running, but with the plans to move the api to the server side, that should not be an issue.
ability to query server for available simple checks would be useful for debugging in some cases, too - seeing whether a specific module has loaded etc