It would be nice to have the current group (for the current course) a person is a member of, provided in the LTI handshake. Use case: We have an LTI app that generates surveys. We want to divide a course into different groups, and assign different surveys to each group. We can get a list of available groups in many ways; via com.instructure.Course.groupIds, API call, or simply by looking at the web interface and copying down the group id that shows up in the restful urls. Unfortunately, there is no current option to provide the group membership in the LTI call.
The LTI variable substitution document currently has:
I'm not sure if that can be plural or not, but the point is, to return an id or ids that are a subset of com.instructure.Course.groupIds