If you use ChatGPT, you already have access to Codex. At the time of writing, it’s available to both free and paid users. You can download it as a desktop app for Windows or macOS. It’s incredibly powerful, but most people ignore it because they assume it’s only meant for programmers. I understand why—after all, the word “code” is right there in its name—but Codex is too useful to overlook. Here are three reasons why I prefer it over the regular ChatGPT app.

Codex can read and create files directly on my system

It doesn’t just answer you—it does the filing too

This is the biggest advantage Codex has over regular ChatGPT. With Codex, you can give the AI direct access to your computer’s file system. That means it can create files and folders for you automatically. Not only that, it can also edit existing files, rename them, move them, or even delete them.

Now, if that doesn’t sound particularly impressive, here are a few practical examples.

Let’s say you use ChatGPT to research a topic. Normally, the workflow looks something like this: you ask ChatGPT to do research > read the response > copy the text > open a text editor > paste everything > save the file. That’s a lot of manual work. With Codex, the process is much more streamlined. It can research the topic and automatically save the output as a properly formatted file directly into the correct folder on your system.

I personally use it to populate my Obsidian vault with notes and ideas. Like ChatGPT, Codex can transcribe voice input, so I often do unstructured thought dumps and let the AI structure and organize everything for me. It creates multiple Zettelkasten-style atomic notes, with each note focused on a single idea, and automatically adds them to my Obsidian vault.

This one workflow change has dramatically streamlined how I capture and organize ideas.

Codex is not just a chatbot—it’s a workspace

It feels more like a super app

At first glance, Codex looks similar to ChatGPT. There’s a familiar conversational interface with an input box in the middle and a sidebar full of chats. But once you start using it, you quickly realize it’s designed more like a workspace than a traditional chatbot.

For starters, almost every file you create in Codex can be previewed directly inside the app. A side panel can render text documents, Markdown files, images, and even code. If you generate HTML, Codex includes a built-in browser that renders the page for you—allowing you to instantly preview the website you just vibe coded.

That built-in browser is surprisingly useful in other ways too. You can open websites directly inside Codex by pasting in a URL. You can then annotate or highlight specific elements on the web page and ask the AI questions about them. While most browsers are trying to integrate AI assistants into them, Codex is integrating a browser inside the AI assistant—and I frankly think it’s the better idea.

The side panel can also launch a second chat window, allowing you to run two conversations side-by-side. If you’ve ever copied outputs from one AI chat into another, Codex makes the process much smoother.

Another surprisingly useful feature is in-built access to Windows PowerShell. Of course, Codex can execute PowerShell commands on its own if necessary. But if you ever want to run those commands yourself—maybe to see the output or save some tokens—then the option is available and within your reach.

Overall, Codex is designed to reduce context switching and keep your entire workflow in one place. Instead of bouncing between five different apps, you get a single interface where you can research, write, generate files, browse the web, and execute terminal commands.

Codex has ‘skills’—and they’re better than Custom GPTs

The fix for the multi-GPT shuffle you’ve been doing

If you’ve spent time using ChatGPT, you’ve probably experimented with Custom GPTs. You basically get to write a system prompt for a specific kind of task, save it as a Custom GPT, and anytime you want to do that task, you open that GPT, and it already knows what to do. It’s a convenient feature that eliminates the need to constantly copy and paste prompts from a separate library—but it’s not perfect.

The biggest issue arises when your workflow depends on multiple prompts working together in sequence.

For example, let’s say you regularly reach out to potential clients. You might use one Custom GPT to research a prospect, another to generate an offer, and a third to draft the outreach email. Keeping those GPTs separate makes sense because each one stays focused on a specific task, which usually improves output quality. But the obvious downside is that you constantly have to jump between chats and manually carry context from one GPT to another just to complete a single workflow.

Skills offer an elegant solution to this problem.

Similar to Custom GPTs, skills are also specialized prompts—but they’re stored locally on your system. You can technically have hundreds of skills in your setup. Then, while working, you can ask Codex to use a specific skill using the command: /skill-name.

This way, in a single chat, you can call multiple skills, which allows you to essentially chain multiple prompts together. It’s an absolute game-changer, and it’s currently my go-to means for managing all my prompts and workflows.

Codex = ChatGPT 2.0

If ChatGPT is already a key part of your workflow, Codex feels like the next step forward. It keeps the familiar chat-based interface but expands it into a full workspace that can interact with files, run commands, manage workflows, and automate repetitive tasks.