Atelier is a development tool and as such its use requires certain access privileges in order to read, edit, compile and debug classes and routines.
The /api/atelier Web Application as installed requires the %Development resource. Consequently, any Atelier user is required to have a role assigned to them which includes that resource. Note however, that a customer can create their own role that grants any privileges they want to allow Atelier access to the server.
When a user creates an Atelier project it is associated with a connection to a server which in turn is associated with a particular namespace. In order to perform those operations listed above, the user must have at least read and write access to the database for which they intend to make edits. For example if the namespace is USER then the user must have READ,WRITE access to the %DB_USER resource.