Multi part oral exam with various group and individual tasks. There is also a structured interview. You find out if you passed that day. After this you go through the admin of getting into the register.
Starts with the FSO test, then essay questions, then an all-day oral assessment. Prepare ahead of time, and recommend that you practice the oral assessment with others. It's a long process, so prepare accordingly.
I applied online. The process took 6 months. I interviewed at U.S. Department of State (Washington, DC) in Jan 2018
Interview
I took the Foreign Service Officer Test at a test center. I scored high enough to advance to the next phase. I then answered the written Qualifications Evaluation Panel (QEP) questions. However, I was not invited to the Oral Assessment (OA).
Interview questions [1]
Question 1
State recommends answering the QEP keeping the following in mind:
positive examples that demonstrate your abilities
Identify learning experiences
Indicate how your learning experience will contribute to success in your chosen track