Is_deleted field

For all endpoints, i'm looking to receive a flag that represents whether the returned object has been deleted in Clarizen. I've been lead to understand that the 'is_deleted' field is the pertinent field for this need.

However, I do not see an is_deleted field when i make api calls. For example, a call to this endpoint; https://api2.clarizen.com/v2.0/services/metadata/describeMetadata?typeNames=Project&flags=fields

Is there something that needs to be done in order for the is_deleted field to be returned in api responses?