Codex App + GPT 5.3 Codex Is INSANE! - Full Tutorial

All right. So, a couple of days ago, Open AAI just went ahead and launched the Cordex app on the Mac, right? So,

I've been seeing a lot of content on the internet where people are claiming that is cursor done, is codex better than cursor and anti-gravity. And again, just yesterday, OpenAI just went ahead and

launched GPT 5.3 Cordex AI model as well. And what they claim is that GPT

well. And what they claim is that GPT 5.3 Cordex is the most capable agentic coding model. Okay. to date. That is

coding model. Okay. to date. That is

what OpenAI is claiming. And today in this video, I'm actually going to try out GPT 5.3 Cordex AI model right inside of Cordex. And yeah, let's see how it

of Cordex. And yeah, let's see how it goes. And by the way, the whole naming

goes. And by the way, the whole naming convention around Cordex is actually very confusing because OpenA actually have a lot of different products in slightly different verticals and all of them actually have the word Cordex or

let's say name Cordex and I think they could have actually named it in a better way. And again, Cordex is nothing new,

way. And again, Cordex is nothing new, right? I mean, you could have accessed

right? I mean, you could have accessed it on the web and it was there. But

recently they launched their app for Mac OS and yes sadly it is only available for Mac OS and no support for Windows or Linux yet. Maybe in the future they will

Linux yet. Maybe in the future they will add the support. So first of all if you want to try out Cordex all you have to do is to just head over to openai.com/cordex

openai.com/cordex and you can just go ahead and download the same for Mac OS and install the same. So in my case I have already

same. So in my case I have already installed it. So there you go. Here I

installed it. So there you go. Here I

have opened up Cordex and this right here is the Cordex app. And yet another interesting thing is that as you can see it says try with free and go or enjoy 2x rate limits on other plans for a limited period of time. The thing is that even

if you don't have a paid uh let's say chat GPT subscription or if even if you're on the free go or let's say any other subscription well you can now use codex for free for a limited period of time. So you can take it out for a spin

time. So you can take it out for a spin and you know you can actually use it for yourself and get a gist of it and you can do all of that actually for free. So

that's the point. Now in this case I have already opened up Cordex and when you open Cordex for the first time this is going to be the kind of interface that you will see. So it is actually a two-tabed layout. So towards the left

two-tabed layout. So towards the left side you'll be able to find all the threads all the project that you have opened up. And towards the right side

opened up. And towards the right side this is where you will interact with the AI. Now to get started all you have to

AI. Now to get started all you have to do is to just open an existing project or let's say a blank project and you can just go ahead and open it up in here.

So, if you click on this add new project button right here, you'll be given the option to select the project and you can open it up. And there you go. The same

is added in here. And you have the option to add and open multiple projects. For example, if you want to

projects. For example, if you want to parallely work on multiple projects at the same time, well, Cordex allows you to do so. So, you have the option to open multiple projects in here. As you

can see here, I have an AI app, we have an app, and also finance tracker. So,

all of these are individual projects that I have opened up in Cordex. And now

after I select a project towards the right side as you can see here it says let's build and again I can find the selected project and towards the bottom you can find a input area and all you

have to do is to just give your prompt in here and hit enter and the AI gets to work and of course we do have this model selector uh drop-own menu and if I select the same I can find the newly added GPT 5.3 cordex and that is what

I'm planning to use. So I'll select the same and you have the option for selecting the reasoning effort. So here

we have low, medium, high, and extra high. Okay, to keep things fast and

high. Okay, to keep things fast and simple, I'll just go ahead and maybe let's say put it as low. And next step, you can go ahead and give a prompt and hit enter. And you can start working on

hit enter. And you can start working on the same. And you actually have the

the same. And you actually have the option to work on a project locally within your computer or you can actually spin up a cloud instance and let's say connect to GitHub repo and you can just go ahead and give a prompt and ask the AI to do something on a remote repo as

well. So both options are there and as

well. So both options are there and as you can see right now we are in the local project. But if you want to let's

local project. But if you want to let's say connect to a GitHub repo and work on the same well you have options for that too. And this right here is actually a

too. And this right here is actually a finance tracker app. So towards the top I can find the option to open terminal and I'll simply run npm rundev. So this

is basically a simple finance tracker app I created just for demonstrating how codex work. So this is pretty simple. So

codex work. So this is pretty simple. So

you add a transaction. Let's say some amount. Okay.

amount. Okay.

You add some income and there you go. Everything is

beautifully visualized in here and everything updates in real time and we have this onepage simple finance tracker app that I created. And next up, let's just say you want to make some sort of changes to this particular app or you want to add new features or you want to

do just about anything. Well, in that case, first of all, all you have to do is to just add that project in here. So,

as you can see, the same is selected and maybe I can close this one. And after

that, you can go ahead and start by giving a prompt in here. So in this case, let's just say I want to change the entire style of this particular app.

Well, in that case, all I have to do is to just give a prompt in here. And

towards the bottom, you can also find an option that says hold to detect. So you

can keep pressing the button and speak whatever you want to. And as soon as you lift the finger, everything will be transcribed. So you don't have to use

transcribed. So you don't have to use yet another TTS tool for that. So I

basically use that one for this one. Can

you please completely redesign our finance tracker app to make it look even more modern and add some really good animations and stuff?

a basic and simple prompt and now I'll select GPT 5.3 cordex and reasoning maybe I'll put it in medium and again if you select high or extra high the time it takes to complete and go through thinking process is going to be

extremely high so you'll have to wait for a long time and again you also have the option for enabling plan mode so before you actually let the AI do anything if you want to go through a planning process and you want to share

your inputs and you want to see how A is planning to implement everything well you have the option for enabling plan mode but for this one I'll actually just disable tablet and now I'll click on the send button and right now we are working

in local so whatever changes that this AM makes it actually happens right within locally within our machine so that's one more thing and as you can see it says I'll upgrade the app UI to a more modern visual style and add purposeful animations across key

sections and then run a quick build and test check to confirm everything still works so Cordex has actually found out that it is a nextjs app and all right so it will take some time and again you can find exactly what uh you know files the

a is going through and you can find all of that in In which case I'll wait for the AI to complete this task and we can go ahead and analyze the result. We can

take a look at the diff view and you know just take a look at the output. So

let's just wait for it. So as you can see GPT 5.3 cordex is still working on the same and it is actually doing a lot of stuff behind the scenes. And the

thing is that you have the option to run multiple agents in parallel even in the same project. For example, let's just

same project. For example, let's just say I want to add a new about page or a new feature or anything as such to this exact same project. Well, I can just go ahead and let's say create a new thread.

And I can simply go ahead and say, can you please create a new about page in the /about route and include the same as project.

Okay. And now I can hit enter. And as

you can see right now, we have like two agents running in parallel doing completely different things. And as you can see, this will go ahead and add a new about page to the existing uh route.

All right. And if I click on this one.

Okay. So, seems like it is now running the build test. So it should be done.

Okay. So this right here is the updated look of our finance tracker app. And to

be honest, it actually looks way better than earlier. The animations, the

than earlier. The animations, the gradients. Oh, did you see that? This is

gradients. Oh, did you see that? This is

actually sick. Okay. So the front end capabilities like the design capabilities of GPT 5.3 codex is actually good is what I would say. I can

now add a new transaction. Let's say

$56,000 rent.

Rent add expense. Mhm. Everything is

updated. So everything is happening in here. Freelance

here. Freelance job.

Okay, there you go. This right here is the current state of our app. We have

this animations and stuff going on, which is exactly what we asked uh Cordex to do in the first place. So all right, so it is still working on the same. So

basically the idea is that you just go ahead and open a project and then you create a new thread and give a prompt and start working on whatever stuff that you want to. And again you have the option for running multiple agents in parallel. And not just that you can

parallel. And not just that you can actually go ahead and run multiple agents across multiple projects. So in

this one we actually running these two uh agents in the same project. But if I want to let's say uh do something on the app project or a app well I have the option and seems like the

about page is done. Let's see. Okay. So

this right here is the about page that the second agent that we spun up created. All right. So this right here

created. All right. So this right here is the current state of the app. And

this is basically how you use the app.

by the way and waiting for approval. So,

do you want me to run the NexJS production build outside the sandbox so turbo pack can complete? Well, I'll just click on no and just complete it. So,

that is basically the flow and next up towards the top, you can now find a couple more options and right now we are actually running it locally within our computer and the project lives in our computer, right? But as I mentioned

computer, right? But as I mentioned earlier, you have the option for making changes to a remote GitHub repo after you connect and after changes are made.

Well, you can click on this button right here and you have the option for committing or let's say pushing the changes or even creating a PR. So all of that options are there. So if you connected let's say a GitHub repo, you can do it and you also have the option

to run this in the web as well that is Cordex web. So that option is there. And

Cordex web. So that option is there. And

if you click on this button right here, you'll be able to open this project in other ids and tools like cursor, anti-gravity finder terminal Xcode.

So whatever apps that you already have installed on your computer, they will appear in here and you have the option to open it up. And after every changes are made, so towards the right side, you have an option that says toggle div panel. And if you click on the same, so

panel. And if you click on the same, so as you can see here, we have a diff view and you can find all the files to which the AI has made changes to. And you'll

be able to find everything highlighted in green and red obviously similar to every other tools. And you can also find all the unstaged files and staged files.

So you can find complete details in here. So that option is also in here.

here. So that option is also in here.

And next up towards the top left if you look you have two options that is automations and skills. And if you want to, you can actually give superpowers to Cordex by adding external skills. That

is to say, you can add external capabilities or let's say external skills to Cordex to make it even more powerful for a specific domain or use case. For example, in this one, let's

case. For example, in this one, let's just say if I add this Figma implement design or Figma uh skill, what happens is that the AI or Cordex will have much better understanding as to how to implement things related to Figma in a

much better way and it will have additional context and skill and depending on exactly what you're trying to do or accomplish. You can go ahead and add all these skills. You have the option for creating a skill, adding a custom skill or you can just go ahead

and add any of the skills that are already in here. For example, let's just say you are using Sentry in your app for monitoring and stuff. Well, you can just go ahead and add the sentry, you know, skill in here and Cordex will have a

much better time understanding how sentry works, how things should be done and all that. You basically get the point, right? Similar to MCP, by the

point, right? Similar to MCP, by the way. And if you click on automations,

way. And if you click on automations, you'll be able to create automations that are scheduled to be run at a particular time in a particular thread.

Well, you have the option to configure all of that in here. And you even have a couple of templates in here. And you can create a new automation as well. So, all

of those options are in here as well. So

this is basically the overall flow of using GPT Cordex the Cordex Mac OS app.

So all you have to do is to just download and use it straight away and that should be it. And next up yet another cool thing is that Cordex actually comes with MCP support too. So

if I just put the / simple in here as you can see here we can find even more tools and one of them is MCP. And today

in this video, I'll actually show you how we can actually test the project.

Whatever stuff that you created using Cordex to make sure that it doesn't have any security issues, any vulnerabilities or front end issues, anything as such, I'll show you how we can run a complete front end or backend test using

Testbrite. And for that, first of all,

Testbrite. And for that, first of all, I'll just head over to testprite.com.

So click the link in the description below and head over to testprite. And

Testbrite is actually a AI powered software testing agent that you can use right inside of Cordex to test your application. So in this case, we created

application. So in this case, we created a simple finance tracker. So let's just go ahead and try to run a test like a front end test or back end test to make sure that everything works. So first of all, click the link in the description below. Head over to testpr.com and sign

below. Head over to testpr.com and sign up for a new account and log into my account. And once you're logged in, all

account. And once you're logged in, all you have to do is to click on this button right here that says test locally. And next step, you can click on

locally. And next step, you can click on this quick install button right here.

And first of all, you will have to create an API key. So you can click on this create a key option right here. and

then click on uh this button right here that says new API key and you can create a new API key. So in my case I have already created one and I can head back and I can click on this option right here that says other ids and you'll be

able to find a bunch of information in here. Next up, you can open Cordex and

here. Next up, you can open Cordex and then click on settings and then click on settings again and I'll select this option right here that says MCP servers and then click on this option right here

that says add server and next step you can give it a name something like let's say test sprite and after that you need to copy the command that is npx and paste the same in here and copy the

arguments that is this part right here in double quotes right so you just copy that and paste that argument in here next up and environment variables. You

copy the API key like this, paste it in here and you head back to your API key section, copy the API key and then paste it in here and you can just go ahead and click on save button and test sprite MCP

will be added and as you can see the same is added in my case. Next up, I can head back to uh Cordex and I can actually go ahead and ask the AI to run a front-end test. And for that, I can actually go ahead and let's say create a

new thread and I can simply say please run a full front-end test u using test sprite.

So there you go. As you can see, it has opened up this test sprite testing configuration page. And here we need to

configuration page. And here we need to configure a couple of details. So as I mentioned earlier, you can do both front end and backend test using test sprite.

But for this one, I'm actually only doing front end test. So front end is selected. So codebase if you your app

selected. So codebase if you your app has a user login option then you can enter the account username and password in here so that the agent can use those credentials to login to the account and

the development uh port is localhost 3000 and you also have the option to upload a prd. So in this one actually I created a simple uh MD file so I'll select the same and now I'll just go

ahead and click on the continue button.

So it says test pry requires a code summary dojson file in this report. So

I'm creating it from the app code and then continue the automated run. Okay.

So let's just wait for it. All right. So

there you go. As you can see it says generation is in progress. Please keep

your local app server running while we generate your test cases. This may take up to 15 minutes and thanks for your patience. And okay, as I can see test

patience. And okay, as I can see test sprite has planned around 14 different individual tests to be carried out. And

the same is in progress in here. So

there you go. I can find it in here. And

now it will take up to 15 minutes. And

now all you have to do is to sit back and wait while it's done. All right. So

the test execution is now complete. And

if I head over to this MCP test section right here, I'll be able to find the test result in here. So I can maybe open it up. And as you can see, out of 14,

it up. And as you can see, out of 14, only six of them passed and one is still in progress. And you'll be able to

in progress. And you'll be able to filter it by pass, failed, or in progress. And first of all, let's just

progress. And first of all, let's just go ahead and try to let's say open one of these test that was passed. And if I click on the same, the interesting thing is that I'll be able to find a screen recording of the AI agent actually

performing the test on the screen. So if

I click on the play button, there you go. As you can see, it is that AI agent

go. As you can see, it is that AI agent mouse that is actually moving and clicking on all these buttons and doing all these actions. And yeah, as you can see, I just went ahead and ran a full test and I have a complete report in

here. And not just that, I have access

here. And not just that, I have access to the screen recordings of exactly what the AA agent is trying to do and what exactly is the problem. I have like the summary of the problem and all that. And

now the thing is that I can open cordex and open the same thread and I can simply go ahead and give a prompt something like this based on the test report given by test sprite can you please identify all the issues and then

fix it and then I can click on the test send button right here. And now what happens is that based on the test report given by test sprite it will go ahead and analyze the entire report and fix it for us. And as you can see cordex has

us. And as you can see cordex has already started working on the same. So

as you saw this is Cordex and Cordex is now actually free on both free and go plan and you can actually go ahead and make use of it right now and paired with GPT 5.3 Cordex model the kind of results that we could actually expect out of it

is actually good and again the UI capabilities and all that from my brief usage I'm actually impressed is what I would say and if you want to get the best of both world make sure to use GPT 5.3 Cordex model right inside of the

Cordex app and yes sadly it is only available on the Mac and if you want to try it on the web you have the option and that's pretty much all I wanted to show you in today's video. I hope you guys found this video useful.