22 USC 3946 - Career appointments

(a) Trial period under limited appointment 
Before receiving a career appointment in the Service, an individual shall first serve under a limited appointment as a career candidate for a trial period of service prescribed by the Secretary. During such trial period of service, the Secretary shall decide whether
(1) to offer a career appointment to the candidate under section 3943 of this title, or
(2) to recommend to the President that the candidate be given a career appointment under section 3942 of this title.
(b) Decisions by Secretary 
Decisions by the Secretary under subsection (a) of this section shall be based upon the recommendations of boards, established by the Secretary and composed entirely or primarily of career members of the Service, which shall evaluate the fitness and aptitude of career candidates for the work of the Service.
(c) Foreign Service Grievance Board decisions 
Nothing in this section shall be construed to limit the authority of the Secretary or the Foreign Service Grievance Board under section 4137 of this title.