How to Get Started with Codex | Introduction to Registration, Initial Setup, and Usage [AI Agent | OpenAI | AI Utilization | Non-Engineers | ChatGPT | AI Tools | Development Efficiency]

Hello, Makari here.

When it comes to AI agents, I've been relying entirely on Claude Code until now, but...

I'd heard Codex was amazing and kept thinking I should try it out, but several months have already passed (lol).

This time, I finally got around to registering for Codex.
You can register and try it out even on the free plan😊
And it was easier to set up than I thought!

In this article, I've summarized everything from registration and initial setup to how to use it.

I've been wanting to start using Codex...!
I hope this serves as a helpful reference for those who feel the same.

What is Codex?

Codex is an AI agent from OpenAI, the company that provides ChatGPT.

By simply giving instructions in the chat box, you can create apps and tools, or automate operations in your browser.

Since it can be used with a similar feel to ChatGPT, I think it's easy to use even for those touching an AI agent for the first time💡

I had been using Claude Code as my main tool, but since I was able to carry over my Claude Code settings and such to Codex, I was able to start using it more smoothly than I expected.

Beyond creating apps and tools, it can also handle tasks you find a bit tedious, such as:
・Organizing folders
・Renaming photos by date
・Helping with browser-based tasks
This is also a major appeal of Codex.

Codex Setup Procedure

There seem to be various ways to register for Codex, but this time I registered via the web version of ChatGPT.

Download the Codex app

1. Open ChatGPT and click "Codex" in the left-hand menu

2. Since I am using a Mac, I clicked on "Download for macOS".

3. When you double-click to open the downloaded Codex.dmg file,

4. The installer screen will appear. Drag and drop the Codex icon into the Applications folder on the right.

The installation is now complete.

5. Open your list of applications and open "Codex".

6. A confirmation screen will appear asking if you want to open the application; click "Open".

7. Click "Continue with ChatGPT".

Logging into Codex

Next, we will log in using your ChatGPT account.

1. Select your account.

2. Enter your phone number.

3. An authentication code will be sent to your mobile phone, so enter the "code"

4. Click "Continue"

Launching Codex

1. You will see "What do you do for work?", so
select the one that applies and click "Continue"
or
click "Skip"

2. For access permissions to files in your desktop folder,
click "Allow"

If you are using Claude Code,
you can carry over your settings, projects, and recent chat history.

3. If you want to carry them over, click "Continue";
if you do not want to, click "Skip"

4. If you are importing, select the items and click "Continue"

5. You can set up Codex mobile later, so "Set up later" is fine

Registration is now complete!

If you carried over your Claude Code data, you should see your data in "Projects" in the left-hand menu!

Check the settings

Before you start using Codex, it is recommended to check the settings.

Select "Settings" -> "Settings" in the bottom left of the Codex app

......................

General Settings

First, let's look at the "General" settings.

・Regarding "Full Access" under "Permissions," I think it is safer to keep it "Off" at first.

By keeping it "Off," it will confirm your actions every time you work.

・Select "Japanese (Japan)" for "Language"
・It is convenient to set "Prevent sleep while running" to "On"◎

Computer Use

Let's configure settings so that Codex can use other apps on your computer and your browser.

1. Click "Computer Use" in the left menu

2. Install "Any App" and "Google Chrome."

3. First, install Computer Use.
By installing this, Codex will be able to operate apps on your computer.

4. Next, install "Chrome"
By installing this, Codex will be able to operate your browser.

5. Click "Open" for the "Codex Chrome Extension"

6. Click "Add to Chrome"

A message saying "Add 'Codex'?" will appear, so click "Add extension"

"Codex" has been added to Chrome!

It is a good idea to pin Codex.

How to use Codex

From here on, we will actually start using Codex✨

Prepare a working folder

Before you actually start working, let's prepare an empty folder.

Click "Work on project" at the bottom left of the chat box and select the empty folder you just created.

Click "Trust all"

Now you are ready to use Codex😊

Give instructions via chat

Using Codex is very simple.

Just enter the task you want to request in the chat box.

This time, I decided to have it automatically move unnecessary emails in Gmail to the trash.

▼ Instruction text

All you have to do is ask for the operation you want performed.

↓

It will confirm with you every time before performing a task.
*You can also change this in the settings

Completed in a flash!

It can be used just like the Claude Code desktop app version💡

How to check your credit balance

To check your remaining credits, click "Settings" in the bottom left → "Remaining Usage"

On the free plan, just that one task used up 75% of the monthly allowance👀!

The free version is definitely just for trial purposes.

Upgrade to the paid version

Upgrading is essential if you want to use it seriously.

Click "Upgrade".

(The ChatGPT website will be displayed)

We recommend starting with the 3,000 yen "Plus" plan.

Click "Upgrade to Plus".

Enter your payment method and other details, then click "Subscribe".

It's great that the limits are also relaxed in ChatGPT, which is a nice bonus 😊

When you open Codex...
The "remaining usage" has definitely increased, hasn't it? 😊

You can check the details in "Settings".

Click "Usage and Billing" in the left-hand menu.

• Current plan
• Credit balance
• Usage limits
and more can be checked here.

You can also cancel your plan from this page ◎

Summary

In this article, I introduced Codex.

I hope to improve work efficiency by integrating it well with tools like image generation in ChatGPT Image 2.0🌱

I would also like to record any other useful ways to use it on note😊

Thank you for reading until the end.

Related Articles

Basically, I think anything you can do with Claude Code, you can also do with Codex💡