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Day 2 of 52 · about 15 min · Basics

Explore a codebase and make your first change

Before you hand Claude real work, watch how it reads a project, what it asks before it acts, and how you say yes or no to an edit.

You’ll finish with

  • A plain-words tour of the project, from Claude
  • One small change you approved or rejected yourself

You’ll need

  • Claude Code installed and logged in, as on Day 1
  • The practice project, or your own project in git
Start from the practice project as of Day 1 (.zip, 9 KB)

Before you start

Tell us about your setup and the steps change to fit it. Your answers stay in this browser, and you can change them at any time.

Which system are you on?

Commands differ between systems. Pick the one you’ll run Claude Code on.

The steps

One step at a time. When a step’s check matches, tick it and the next one opens.

0 of 4 steps done0%

  1. Step 1 of 4: Start in Manual mode

    Start Claude Code so it asks before every edit.

    New sessions usually start in auto mode, where Claude edits without asking. Today you want to see each edit first.

    Terminal

    Run: claude --permission-mode default

    What happens: The status bar under the prompt shows ⏸ manual mode on.

    Run it in the project folder. Shift+Tab switches modes later.

    Check it worked

    You see ⏸ manual mode on under the prompt.

    If it didn’t work

    Shift+Tab does nothing on Windows

    Press Alt+M instead. It cycles the same modes.

  2. Step 2 of 4: Ask Claude to explain the project

    Ask what the project does and where things live, and let Claude read.
    Paste into Claude Code
    What does this project do? Explain the folder structure, where the main logic lives and how to run the tests. Don't change anything yet.

    In order:

    1. You

      You ask a question

    2. Tool

      Claude reads files

      No prompt for reads inside the project

    3. Claude

      Claude explains

    Read-only commands such as ls and git log don’t ask either.

    Check it worked

    For Acme Quotes, the answer points to src/quote.js for pricing and npm test for the tests. For your project, you recognise the description.

  3. Step 3 of 4: Ask for one small change

    Ask for a small change, read the edit Claude proposes, then answer.
    Paste into Claude Code
    Make node src/cli.js --help list each role from data/rates.json with its hourly price. Change only src/cli.js.

    In your own project, ask for something as small, such as a clearer error message.

    In order:

    1. Claude

      Claude proposes the edit

    2. Tool

      Claude Code shows the change and asks

    • If you choose Yes

      The edit is saved

    • If you choose No

      Nothing changes, and the turn stops

    • If you press Tab on No and type a note

      Claude gets your note and keeps working

    Nothing touches the file until you answer.

    Check it worked

    You read the change before answering. If Claude asks to run a command, such as node src/cli.js --help, the prompt names it; choose Yes.

  4. Step 4 of 4: Check the result yourself

    Run the command the change touched and make sure the tests still pass.
    Terminal

    Run: node src/cli.js --help

    What happens: Lists the four roles with their hourly prices.

    Run: npm test

    Works the same in PowerShell.

    Check it worked

    After Yes: the roles are listed and the tests show fail 0. After No: src/cli.js is unchanged.

Finish · 4 of 4 steps to go

You’ve seen Claude read, propose and wait

Use Manual mode while you learn what Claude does. Once you trust it on a kind of task, press Shift+Tab to switch back.

What you’ll have checked

  • The status bar showed ⏸ manual mode on
  • You approved or rejected an edit after reading it

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Claude Code for your team

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Questions

Questions about Day 2

Why did Claude edit a file without asking?

The session was in auto mode, where a separate classifier reviews actions instead of you. Start with `claude --permission-mode default`, or press Shift+Tab until the status bar shows manual mode.

Sources

Checked against the official Claude Code docs on .

Independent resource, not affiliated with Anthropic. HorizonLux wrote this lesson; Claude Code is made by Anthropic.