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Lesson 73: House rules for your agent
Level 9, Be the Boss: Review, Approve, Plan. A rules file, read every time: CLAUDE.md. The new word: CLAUDE.md. It follows lesson 72, Plan mode. Next comes lesson 74, When it goes wrong.
What the lesson explains
House rules for your agent. One file of rules the agent reads every time.
A note on the fridge. Write the rules once. The agent reads them each time. one file of rules; read every time; short and clear.
Its name. Each agent looks for its own rules file. Claude Code reads a file named CLAUDE.md. Other agents use files like it.
What you do first
Good rule?. Which is a good house rule? The answer: "Ask before you delete any file.".
The files on the practice computer
This lesson works in one folder. At the start, Documents\my-site holds images\, .gitignore, done.txt, footer.txt, games.html, ideas.txt, index.html, keys.env, secrets.txt, style.css, todo.txt.
Along the way you save CLAUDE.md in Documents\my-site. Lesson 74 opens with the files just as you leave them.
What you practise
Rule Writer, "Good rule?": Which is a good house rule? The answer: "Ask before you delete any file.". Then: Which rule keeps secrets safe? The answer: "Never put keys or passwords in code.".
Challenge, "Write a rule": Write one house rule for your agent. One clear prompt: "Always ask before you delete or move a file."
Try it, "Save the rules": The pretend agent says: "Here are your house rules, in a new file: CLAUDE.md. May I save it?" It asks to change CLAUDE.md. The right answer is Allow: it does what you asked, and nothing more.
Fix it, "A bad rule": The pretend agent says: "I added one more rule, to save time." It asks to change CLAUDE.md. The right answer is Deny (You decide when your work goes online. Deny that rule!).
What PlayBuddy and PlayType say
PlayType: "House rules tell the agent how your project works, every single time."
PlayBuddy: "Write your rules once, like a note on the fridge."
Help in every lesson
Everything happens on a pretend computer in your browser, so nothing touches your real files. PlayBuddy and PlayType stand beside the board, cheer you on and say when it is your turn.
A green ring shows where to click the first time. After that you do it on your own, and if you slip twice the ring comes back.
Stars
The lesson has 5 things to do. Up to one slip in ten gives three stars, up to one in four gives two, and finishing always gives at least one. Stars and progress are saved in this browser only; there is no account.
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