Open the wizard. That is the whole program. No install.
AGENTS.md in the project, or pick another name the tool actually reads.The words in the file are yours. ChuuInstruct formats, orders, and checks them.
Nothing you type is sent anywhere. Close the tab and it is gone.
The wizard on this site is the standard one: both stops on the slider, all eleven built-in sections, every thinking style and underlay, and the checks. It writes the whole file.
The copy you buy adds one screen — Advanced, where you write your own rules. Each line goes into the section it belongs in, and before the file is built it reads your lines back to you: vague words, rules shaped like enforcement, anything that contradicts a rule already in the file, repeats, and how many instructions you are up to. The page footer says which one you have.
View-source copy is accepted, which is why the paid screen is not in this page at all rather than hidden in it. ChuuWrite is separate and paid. It is not on this site.