They possess a simple artificial intelligence and can act independently to support their user in combat. When not in use, they exhibit a childlike personality and provide much of the humor in the series, while also being used to elaborate on Shirow's philosophy and ideas. Their AI does not include typical safeguards as they are military hardware, but because they possess emotions, they are closely monitored for signs of instability. The Fuchikomas within Section 9 are synchronized nightly or after missions to share their experiences and allow the entire group to learn from them.
Mechanically, they have four legs and two simple hands with three fingers on extensible arms which double as machine guns. The "face" consists of a large main lens and two smaller sensors with a "mouth" below, which is commonly a grenade launcher but sometimes a heavier machine gun. The pilot sits in a hunched position inside a large posterior pod with interface cables leading to the standard ports in the user's neck for direct control, but the Fuchikoma can also be given orders to act without a pilot.
They can handle many different types of terrain, and are able to walk up walls, rappel, walk, or extend wheels from their feet to drive. They are also submersible.
Fuchikomas appear in the graphic novel of Ghost in the Shell (Kōkaku Kidō-tai) and a PlayStation game of the same name, where the player spends the entire game playing as a member of Motoko Kusanagi's team, who is inside a Fuchikoma at all times.
In the TV series Ghost in the Shell: Stand Alone Complex, they are replaced by Tachikomas which act similarly, but look different, standing taller, and instead of a single large "eye" lens, they have 4 independent rotating sensor pods with 3 sensors each. The AI of Tachikomas is considerably more advanced.
At the end of the TV series Ghost in the Shell: S.A.C. 2nd GIG the Tachikomas sacrifice their AI's in order to prevent a nuclear detonation. They are replaced by Fuchikoma/Tachikoma hybrids, referred to as Uchikomas. There is some controversy over this name, as the Bandai DVDs refer to these tanks as "Fuchikoma", due to a misunderstanding dealing with the pronunciation of the "hu/fu" sound and comic source. However, all artbook and model kit resources clearly label these hybrid machines "Uchikoma".