When the player clicks on a block, they receive a tool from the ServerStorage. How can I make sure that the tool is always equipped when the player has it? Thanks in advance!
You can disabled the backpack. When you disable the backpack and a player picks up/holds a tool they cannot unequip the tool.
To disable the backpack you need a Local Script in StarterGui and put this:
game.StarterGui:SetCoreGuiEnabled(Enum.CoreGuiType.Backpack, false)
This will disable the back pack thus allowing you to stop a player from unequipping an item.