# Your first real edit

Course: Claude Code from Zero — https://zero2vibecode.com/learn/claude-code
Canonical URL: https://zero2vibecode.com/learn/claude-code/2-1-first-real-edit

The agent changed a file. Now you do the part that is yours: see what appeared, read it, run it, and save a checkpoint you can come back to.

You asked for a date-formatting helper. The agent says it added one. Here is the part that belongs to you.

## Step 1: see what actually changed

The agent's summary is a claim. `git status` is evidence — it shows you every file that is new or different, with no interpretation.

Do that in the terminal below, then read the new file with `cat`, then commit it.

**Two different questions.** 
`git status` answers "which files changed". `git diff` answers "what changed inside them". You want both, in that order, on every turn that touches code.

## Step 2: read the diff

Green lines were added, red lines were removed. You are not grading style. You are asking three things:

1. **Is this what I asked for?**
2. **Did anything change that I did not ask about?** A "helpful" reformat of a whole file will drown the actual change in noise.
3. **Do I understand every line?** If not, ask. "Explain line 14" is a perfectly good request.

## Step 3: run it

Reading catches roughly half the problems. Running catches the other half — the invented function, the import that does not resolve, the option that never existed in that library.

Start the app. Click the thing. Run the tests. Whatever "run it" means for your project, do that, not a mental simulation of it.

## Step 4: commit

You are happy with it. Save the point.

```
git add .
git commit -m "add formatDate helper"
```

That commit is now a place you can return to from any mess the next turn creates. This is the single habit that changes how working with an agent feels: with a clean repository behind you, a bad turn is an inconvenience instead of a disaster.

**One turn, one commit.** 
Commit after every turn you are happy with, not at the end of the day. A commit per turn means "throw away the last change" is always a precise, painless operation.

## What a good first edit feels like

Small. Boring. Reviewed in ninety seconds. Committed.

If your first real edit is a nine-file feature, you have skipped the part where you learn what this tool does well. Do three small ones first. You will read diffs faster, you will spot the invented function sooner, and you will have three commits to prove it.

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