Tools are essential for worker efficiency. There are three types: Stone Tools (Blacksmith, early game), Iron Tools (Blacksmith, mid-game), and Steel Tools (Blacksmith, late game, requires coal). Workers consume tools over time; running out of tools severely reduces productivity across all professions.
Establish a Blacksmith early to produce Stone Tools. As your iron and coal supply stabilizes, upgrade to Iron and then Steel Tools. Steel Tools are the most durable and efficient. Always maintain a surplus of tools. If you lack the raw materials for tool production, trading for them is a viable, though often expensive, alternative.