How Do I Use the getPermittedActions Function?

I am creating a server-side follow-up action that modifies a work item after a user has hit save while making a specific change. My follow-up action modifies the description attribute (which is not the same attribute that the user touched). I want to handle the case where the user had permissions to modify the custom attribute that I care about, but they do not have permissions to modify the description field. In this case, if I don't catch that scenario, my follow-up action will fail and will prevent the user from being able to save the work item. I would prefer for my follow-up action to fail silently and allow the user to commit their save.

In researching this, I found a function that seems promising, the IServerProcess#getPermittedActions function. The description for the function reads:

boolean [] com.ibm.team.process.service.IServerProcess.getPermittedActions(String projectOperationId, String [] actions) throws TeamRepositoryException

Queries whether the current user has permissions to perform each of the given actions for the given project operation. Each entry in the returned array specifies whether the user has permissions for the corresponding action in the given array.

Parameters:
     projectOperationId the identifier of the project operation
     actions the collection of actions to consider

Returns:
     an array of booleans which specifies whether each of the given actions are permitted

Throws:
     TeamRepositoryException

Here is how I've tried to use it so far:

IProcessServerService pss = getService(IProcessServerService.class);
IServerProcess sp = pss.getServerProcess(operation.getProcessArea());
String [] actionList = {"modify/description", "description"};
boolean [] resultPermissions = sp.getPermittedActions("com.ibm.team.workitem.operation.workItemSave", actionList);

I'm not sure if I'm populating my "actionList" with the correct values. The values shown above were to try and catch either possibility. Evidently the function doesn't have issues if you pass it an action that doesn't exist. For the case above, I changed the permissions in my test project area so that I could not modify the description field, then I ran the follow-up action. The resultPermissions array contained "false, false" for both actions. I then changed the permissions to re-enable the ability to modify the description and triggered the follow-up action again. The result was still "false, false". This suggests to me that I have not picked either the correct actions or the correct projectOperationId.

Has anyone used this function before? Can you describe how to use it correctly?