Done I hope. Needs testing and type checker updates.

waiting on https://github.com/space-wizards/space-station-14/pull/422

Content.Server/GameObjects/Components/Items/HandsComponent.cs

@@ -1,9 +1,11 @@
 using Content.Server.Interfaces.GameObjects;
 using SS14.Shared.GameObjects;
 using SS14.Shared.Interfaces.GameObjects;
+using SS14.Shared.Utility;
 using System.Collections.Generic;
 using System;
 using System.Linq;
+using YamlDotNet.RepresentationModel;
 
 namespace Content.Server.GameObjects
 {
@@ -32,10 +34,28 @@ namespace Content.Server.GameObjects
         public override void Initialize()
         {
             inventory = Owner.GetComponent<IInventoryComponent>();
+            base.Initialize();
         }
 
-        public IEnumerable<IItemComponent> GetAllHands()
+        public override void OnRemove()
         {
+            inventory = null;
+            base.OnRemove();
+        }
+
+        public override void LoadParameters(YamlMappingNode mapping)
+        {
+            foreach (var node in mapping.GetNode<YamlSequenceNode>("hands"))
+            {
+                AddHand(node.AsString());
+            }
+            base.LoadParameters(mapping);
+        }
+
+        public IEnumerable<IItemComponent> GetAllHeldItems()
+        {
+            throw new NotImplementedException();
+            /*
             foreach (var slot in hands.Values)
             {
                 if (slot.Item != null)
@@ -43,6 +63,7 @@ namespace Content.Server.GameObjects
                     yield return slot.Item;
                 }
             }
+            */
         }
 
         public IItemComponent GetHand(string index)
@@ -56,6 +77,8 @@ namespace Content.Server.GameObjects
         /// </summary>
         private IEnumerable<string> ActivePriorityEnumerable()
         {
+            throw new NotImplementedException();
+            /*
             yield return ActiveIndex;
             foreach (var hand in hands.Keys)
             {
@@ -66,6 +89,7 @@ namespace Content.Server.GameObjects
 
                 yield return hand;
             }
+            */
         }
 
         public bool PutInHand(IItemComponent item)
@@ -127,5 +151,37 @@ namespace Content.Server.GameObjects
             var slot = hands[index];
             return slot.Item != null && slot.Owner.CanDrop(slot.Name);
         }
+
+        public void AddHand(string index)
+        {
+            if (HasHand(index))
+            {
+                throw new InvalidOperationException($"Hand '{index}' already exists.");
+            }
+
+            var slot = inventory.AddSlot(HandSlotName(index));
+            hands[index] = slot;
+        }
+
+        public void RemoveHand(string index)
+        {
+            if (!HasHand(index))
+            {
+                throw new InvalidOperationException($"Hand '{index}' does not exist.");
+            }
+
+            inventory.RemoveSlot(HandSlotName(index));
+            hands.Remove(index);
+        }
+
+        public bool HasHand(string index)
+        {
+            return hands.ContainsKey(index);
+        }
+
+        /// <summary>
+        ///     Get the name of the slot passed to the inventory component.
+        /// </summary>
+        private string HandSlotName(string index) => $"_hand_{index}";
     }
 }

Content.Server/GameObjects/Components/Items/InventoryComponent.cs

@@ -2,10 +2,12 @@ using Content.Server.Interfaces.GameObjects;
 using SS14.Server.GameObjects;
 using SS14.Server.GameObjects.Components.Container;
 using SS14.Server.Interfaces.GameObjects;
+using SS14.Shared.Utility;
 using SS14.Shared.GameObjects;
 using SS14.Shared.Interfaces.GameObjects;
 using System;
 using System.Collections.Generic;
+using YamlDotNet.RepresentationModel;
 
 namespace Content.Server.GameObjects
 {
@@ -36,6 +38,18 @@ namespace Content.Server.GameObjects
             base.OnRemove();
         }
 
+        public override void LoadParameters(YamlMappingNode mapping)
+        {
+            if (mapping.TryGetNode<YamlSequenceNode>("slots", out var slotsNode))
+            {
+                foreach (var node in slotsNode)
+                {
+                    AddSlot(node.AsString());
+                }
+            }
+            base.LoadParameters(mapping);
+        }
+
         public IItemComponent Get(string slot)
         {
             return _GetSlot(slot).Item;
@@ -106,14 +120,14 @@ namespace Content.Server.GameObjects
             return item != null && container.CanRemove(item.Owner);
         }
 
-        public void AddSlot(string slot)
+        public IInventorySlot AddSlot(string slot)
         {
             if (HasSlot(slot))
             {
                 throw new InvalidOperationException($"Slot '{slot}' already exists.");
             }
 
-            slots[slot] = new InventorySlot(slot, this);
+            return slots[slot] = new InventorySlot(slot, this);
         }
 
         public void RemoveSlot(string slot)

Content.Server/Interfaces/GameObjects/Components/Items/IHandsComponent.cs

@@ -13,7 +13,7 @@ namespace Content.Server.Interfaces.GameObjects
         /// <summary>
         ///     Enumerates over every held item.
         /// </summary>
-        IEnumerable<IItemComponent> GetAllHands();
+        IEnumerable<IItemComponent> GetAllHeldItems();
 
         /// <summary>
         ///     Gets the item held by a hand.
@@ -70,5 +70,30 @@ namespace Content.Server.Interfaces.GameObjects
         ///     True if the item can be dropped, false if the hand is empty or the item in the hand cannot be dropped.
         /// </returns>
         bool CanDrop(string index);
+
+        /// <summary>
+        ///     Adds a new hand to this hands component.
+        /// </summary>
+        /// <param name="index">The name of the hand to add.</param>
+        /// <exception cref="InvalidOperationException">
+        ///     Thrown if a hand with specified name already exists.
+        /// </exception>
+        void AddHand(string index);
+
+        /// <summary>
+        ///     Removes a hand from this hands component.
+        /// </summary>
+        /// <remarks>
+        ///     If the hand contains an item, the item is dropped.
+        /// </remarks>
+        /// <param name="index">The name of the hand to remove.</param>
+        void RemoveHand(string index);
+
+        /// <summary>
+        ///     Checks whether a hand with the specified name exists.
+        /// </summary>
+        /// <param name="index">The hand name to check.</param>
+        /// <returns>True if the hand exists, false otherwise.</returns>
+        bool HasHand(string index);
     }
 }

Content.Server/Interfaces/GameObjects/Components/Items/IInventoryComponent.cs

@@ -62,7 +62,7 @@ namespace Content.Server.Interfaces.GameObjects
         /// <exception cref="InvalidOperationException">
         ///     Thrown if the slot with specified name already exists.
         /// </exception>
-        void AddSlot(string slot);
+        IInventorySlot AddSlot(string slot);
 
         /// <summary>
         ///     Removes a slot from this inventory component.