I've been looking through the REST Api,

GET /api/variables/names HTTP/1.1

Seems to show you the names of the variables in use. But there is no existing way to get a definition of what these are through the REST API. This would be highly useful for automated testing.

Some of these system variables are also used inside of the deployment variables. It would be nice to be able to have access to the system variables, in order to resolve the environment variables.

This way a tester could read from Octopus deploy REST API, and execute specified tests.