A small working barracks for your city watch/guard. If you have people sharing beds and working shifts this barracks could house 60+ Guards. The fortified walls provide security and a defendable location in dire situations.
Prisoner cells and holding - Short time holding and stocks in 1st courtyard, prisoner cells (including three magic resistant cells) and integration room underground. Stocks outside main gate for public humiliation.
Courthouse - Serving justice and passing judgment on the criminals brought in.
Stables - Can house up to 10 houses, room close by for the stable hands.
Training courtyard - Guards can hone their skills in the training yard, and are expected to train every day.
Armory - Enough swords and equipment for everyone!
3 Barracks rooms - Each with 10 beds.
Guards common room and canteen - When not on duty they can eat, drink and relax here. That way they wont cause trouble in the city getting drunk in the taverns.
Staff quarters - Serving staff have easy access via the side corridor to get supplies into the kitchen/cellar without getting in the way of troops in the courtyard.
Cellar - Well stocked if necessary the barracks could hold out for a while in siege conditions. Also can be home to a wizard if needed. Can be good to magically seal the cells to prevent escape.
Elite guards rooms - Located on the first floor these rooms are less cramped and more luxurious.
Officers rooms - A dining/briefing room for the Captain and officers. Two bedrooms and shared office for the Lieutenants. Captains office with his room upstairs.