Active time: Approximately 20–30 minutes.

Today’s outcome: Describe a broken behaviour, ask a coding agent to choose and explain a diagnostic check, approve one repair and prove that the app works again.

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**Quick links: LinkedIn lessons · WhatsApp group · The Builder Course website .

Setup . Day 1 . Day 2 . Day 3 . Day 4**

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💡 Using Claude Code?

This lesson uses Codex. If you use Claude Code, replace AGENTS.md with CLAUDE.md inside copied prompts.

When the lesson asks for a fresh Codex task, start a fresh Claude Code conversation in the same challenge folder. The remaining steps are the same.

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Today, you will run a controlled recovery drill.

The goal is not to learn a terminal command or become a JavaScript expert. The goal is to practise what to do when an agent-created project stops working.

Why this matters

When an app breaks, you may not know which technical tool to use. That is normal.

The coding agent can propose an appropriate check. Your job is to:

• describe what you observed;
• ask what the agent wants to check and why;
• confirm that the check is safe;
• approve investigation before repair; and
• verify the result in the product.

Today’s recovery sequence is:

Observe → agent proposes a check → you approve → agent runs it → diagnose → repair → retest

The agent chooses the tool. You stay in control of the decision.

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Before you begin

Open the same challenge folder in VS Code.

Confirm that you can see:

• AGENTS.md or CLAUDE.md
• index.html
• styles.css
• script.js

Open the app and confirm that it currently works.

Test these actions:

1. Add a task.
2. Mark it complete.
3. Use the clear-completed-tasks button.

Do not begin the recovery drill until all three actions work.

Your required action