Just so there's a centralized place where the loose term 'stone age' can be refined into more proper answers, here's a brief list of what kobolds are allowed to build or not. Items with ? may need clarification.
Yes: All Wood Blocks/Tools All Basic Stone Blocks/Tools (No Stone Bricks) Fishing Rods Carrots on a Stick Leads Bow/Arrows Beds Melon/Pumpkin Farms Leather Armor Boats Simple Redstone Traps (Tripwires, basic circuits, redstone torches) Mushroom 'elixirs' Dying (?) Replanting trees (?) Snow Golems (No snow, so kinda futile)
No: Minecarts/Cart Tracks Wheat Farms Carrot/Potato Farms (?) Bonemeal Plant Growth Complex Redstone Things (repeaters, logic circuits, mob grinders, etc) Iron+ Armor (Includes Chainmail, Scavenged is ok) Iron+ Tools (Scavenged is ok) Horses and horse accessories Bread Cake Pumpkin Pie Iron Golems Homemade Enchantments (?) Homemade Alchemy Products (?) Tree Farms
A creative bold found himself in trouble a couple weeks ago and decided to throw a bunch of mushrooms at the big meanies, saying they kicked up a sneeze inducing spore cloud. As a strictly roleplay measure, it worked, and I decided to give him the real thing.
Kobold stinkbombs and smokebombs are cobbled together from whatever materials are readily available. They are never very potent, but often enough to buy a few precious seconds. Glimkin is a scholar-bold, and can make them in small quantities.
On a similar note, if we get a dedicated craftsbold, I am willing to provide some lovely sharpened sticks spears with some knockback and just enough damage to make them worth considering as a weapon. Fighting up close is for tougher races.
There is nothing mechanical that can be done to prevent people from making golems, since they magically spring to life if common blocks are in the right shape. That said, Iron Golems are generally considered dwarf constructions, complicated and sturdy guardians constructed from the blood of the earth by expert hands, and sometimes said to house the very souls of dead dwarves.
Snow golems on the other hand, are ridiculous fanciful nonsense that no sane adult would ever expect to function, so of course kobolds know all about making them.