The CAOS Tool is a Windows program developed by Creature Labs to write and inject CAOS code into the Creatures 3/Docking Station engine. It was the tool used internally by Creature Labs when they made the games, and was originally sold through CDN but is now a free download. You need to use the registration key provided on the official website to run the tool.
Features include that it is fully syntax aware and will display CAOS errors in red. The error window will give you clues as to why your code failed. All cos files can be formatted and are colour coded to improve readability.
The CAOS tool will let you inject particular scripts directly into the game. It will let you browse the scriptorium of the game and view particular scripts.