This may or may not change, and will likely be based on the relevance of the Protagonist's history for the story as it is implemented. Very little is known about the history of the Protagonist. However, it is extremely likely the Protagonist is a D-Class personnel. It is even unknown if the Protagonist is employed at the Foundation at all, and didn't arrive at the facility during the containment breach through anomalous means.
It is currently unknown what position the Protagonist is employed as at the Foundation.