GetRESTProxy() INVALID_FUNCTION error in CXone Studio Snippet

Is it possible to use GetRESTProxy directly within a standard Studio Snippet block without wrapping it in a specific Data Action context? I am attempting to fetch real-time agent status from the CXone Reporting API inside a Studio flow to route calls based on current state. The syntax I am using is:

SET restProxy = GetRESTProxy();
SET response = restProxy.Get("/api/v2/reporting/agents/summary", {"divisionId": "123"});

The flow execution log throws an INVALID_FUNCTION error immediately at the GetRESTProxy() call. I have verified that the Studio script has the necessary permissions and the OAuth token is valid for the reporting scope. The documentation implies this function should be available in the scripting environment, yet the interpreter rejects it as an undefined function.

Is there a specific namespace or import required, or is GetRESTProxy only valid within the newer Flow Designer context? I need to know the correct syntax for invoking REST calls from a legacy Studio Snippet to avoid refactoring the entire flow to Flow Designer at this stage.