Or some kind of tools that allows you to modify the item's condition based on your current type of tool.
There can be 3 quality levels of the tools, and each one repairs weapons and armor better than the other.
Lv1 is Basic Repair Kit - Repairs only basic weaponry found throughout the beginning stages, and garbage stages, at a decent amount.
Lv2 is Advanced Repair Kit - Repairs basic weaponry fully, and can repair advanced weaponry at a decent level. Can repair armors decently.
Lv3 is Top Quality Repair Kit - Repairs basic and advanced weaponry fully. Repairs Armors best.
Tools could have an amount of durability, and as I mentioned this, I noticed that all other items has a condition bar that never degrades, even for food.
Each time you successfully repaired a item, it degrades it's usage by 1 pt out of 100. Each time you repaired but damaged the weapon's max dur, you use up 5pts. Each time you failed to repair the item, you damage the item's max dur AND loses 10pts.
Repair chance depends on level of tools and level of items.
This mod can work with the trader's repair mod, but sometimes the trader cost a lot.
You should do research first before posting "new" ideas. It has existed for quite a while now.
although if he wants to make it for 2.2 I wouldn't mind ;)