Tools are the top-level items in the game. Their production requires orange recipes which you will first have to unlock.
There are six tools in the game, one for each industry. They have two applications, but that is a topic for another time.
To produce tools, you will need Purple components. Purple components require Blue goods, while Blue components require Green ones. Tools are the rarest and the most valuable in-game items.
You need tools to eliminate threats. Create them at the enterprise, head for a dangerous zone of the station and use them.
At the end of each season, new production sites will be distributed among the players who have contributed to the elimination of threats. Those with the highest rating will be able to build enterprises and get more profit.
Tools can be looted from the corpse of a murdered avatar, so be careful when taking them with you to dangerous areas of the station!
You can also use tools at a production to multiply its throughput and make even more items from the same amount of resources in the same amount of time!
Every industry makes tools for some other industry. Light industry makes tools for the heavy industry, etc.