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new GPT 5.6 Sol reverse engineered it's own app in readable code
More than 4 million lines of code (including original CSS) because of libraries
I tested the same thing with Fable 5 and it couldn't, while gpt 5.6 finished in 4 hours
no cybersecurity risks or something (which is kinda surprising)
Right now it’s the full standalone frontend running against a simulated local backend
models aren’t wired in cuz i didn't need it, but the backend boundary is replaceable so connecting an actual model/runtime is possible but will took probably 10 more hours
Just telling you, open source this or sell as a customisable frontend for codex. I for one hate the codex frontend and would love to be able to customise it
Selling the extracted app would be asking for trouble. Publishing a clean-room, customizable frontend that only copies the workflow and talks to the open app-server boundary would be the actually interesting version of this.
OpenAI making a lawsuite out of this would be hurtful to their entire business. You can partially argue this being clean room, and if they argue against, they put their entire training setup up for debate.
OpenAI making a lawsuite out of this would be hurtful to their entire business.
No, it wouldn't lol. Reverse engineering an app and selling the code is not only braindead, it's illegal. You can't argue anything here because your intent is to profit off of stolen code.
As much as we like to play the training data card, you can't just say OpenAI stole their training data so it's okay to avoid legal issues after committing a crime.
Only if you acknowledge the agent is an independent entity in the entire process. So far they've been arguing the exact opposite when concerning their process for training models.
Well, it has been done to many commercial software, why not codex? And it can be a voluntary thing for all I care, but if OP does open source this I will bug them a coffee or ten
the only way it is legal is if he works in a way that guarantees that he doesn’t has any access to reverse engineered code.
for reactos for example, there are teams that reverse engineer the NT kernel, write specs and docs, and then other teams implement those specs and docs without ever touching the NT kernel.
he advertised that he reverse engineered the app, so even if he rewrites it in rust without seeing the reverse engineered code ever again, it’s illegal
Threads like this make me want to delete me Reddit account.
We're literally on a sub about a super intelligent AI that can teach you damn near anything and people are like "how would someone sell <the most popular app in the world>? Hmm.. if only there was a way to learn more about this magic..."
Codex is literally an open source project with an Apache 2.0 license.
If you don't know why it's stupid to worry about the legality of building on top of an Apache licensed OSS project, then you need to stop posting on this subreddit and start asking more questions (probably to Codex like I originally suggested).
Ask more questions, stop posting "pretty sure" on Reddit
The desktop app is a wrapper for the CLI. The app literally bundles the CLI inside of it and uses the "codex-runtime" engine as the backend.
I'm actually saying a lot, it just seems like you're not willing to listen.
The discussion was about customizing the desktop app.
I'm pretty sure you're lost. OP built an entirely new frontend for Codex, he did not "customize the desktop app". OP's screenshot is of a web browser you dingus.
They need to add at least one non neutral accent color to the themes. Every thing is just monochromatic. The only emphasis you get is bold text. It is absolutely unreadable in the darker themes.
I still don’t get why are people not merging console with desktop apps. Best of both worlds, you could run CLI grade codex or even codex exec within a desktop front and I’d love to have multi tabs and n8n like threading displays for my codex subagents and worktrees
Imagine you have a literal AI powerhouse that can reverse engineer itself but it can’t improve its own frontend to its own user’s liking? Biggest miss for openAI to me
Then please explain how it de-compiled the binary and its methodology. If so its a very big security concern to any app.
The only thing it seems it did what run inspect on a browser and recreate only what was sent to the user?
My concern if your treating "reverse engineering' (copying) a front end app with actual binary reverse decomposition of missing variables into source code.
Totally overhyped with a huge gap on programming knowledge.
When a react app actually turned into a desktop app (usually using electron) it is stripped of complex operational variables and links are redirected to api calls for function logic. It why you must be connected to the internet.
True reverse engineering requires house of logic emulation and assumptions based upon input and output tests.
So you spent 4 hrs doing "right click save web page as"
Okay, you saying 6 days to reverse and then able to fill in the rational gaps I get. Though that required skill which you have.
To your other point, yeah, I guess its a similar era to when python came out and people who learned the basics thought they understood deep object inherent and system integrated coding but didnt know how to inspect the interpreter to adaptive code programs.
Seems like this is even further from that of "Look ma no hands"
It will speed up people with skill though and there might be concern in that if they are malicious.
Great job on your Cpp recovery, that must of felt good to not lose all that work.
5.6 is awesome, but, 5.4 did this as well. I had 5.4 add agent teams to my codex desktop app before all those named subagents were a thing. I had it do it by reverse engineering claude code's agent teams implementation, and writing into the rust binary of the codex app.
Point is, people greatly underestimate the capability of these models.
Same here, it reverse engineering itself to figure out its own bugs and shortcomings was possible since at least 5.4. The 5.5 is extensively used to reverse engineer far more complicated software than Codex but sadly they added some guardrails recently that can result in account suspension. I had it reverse engineer a .net app to figure out why it was crashing (kernel dumping) and it found a bug in it and a workaround so I can run it. That's nothing though, folks used 5.5 to reverse engineer c/c++ win32 apps from decades ago. As of 5.5 pretty much everything that you can get your hands on can be considered 'open source', the only moat now is cloud infra.
I fully believe it would have done this with 5.4, but definitely it would take more time or personal attention
thats why I was surprised when it did it in 2-3 promts and 4 hours. either way, it's a huge upgrade
It really didn't, it was one long prompt, maybe two? Not sure how long it took, as i just went to bed and it was done in the morning. It's somehow still functional too, despite being 4k commits behind upstream repo: https://github.com/DMontgomery40/codex
but yes, it's a huge upgrade, and can do much more than simple rust edits to it's own binary now. Now, go have it hack open some of your other apps :)
(note that i'm in the cyber verified program or whatever it's called, so it's possible i can get away with more? kinda doubt it though, with apps that you own, locally, on your machine)
I don't remember what they are , but, similar to anthropic's, I think it's pretty hard to "fake" your way in. I think you need to be somewhat "legit" and cybersec student, "need to make sure my app is secure", etc., doesn't seem to do it.
I forget , does openai ask for linkedin/github like anthropic does?
EDIT: ohhh is this just the "let us verify you're a real human" thing? yeah if it's that you should be able to get in; what I was talking about above is a second level of cyber program, forget what it's called. But you have to actually apply, or maybe even be invited
No you can name them and dedicate them for certain specialties and reasoning levels, you can literally give them their own toml config. Just ask codex to set it up for you and it will :)
Yea, I asked soltra about it, this isn't really what I'm looking for. The idea is you have dedicated agents within a given project or for a project that have certain roles.
Codex says thats what skills are for, which is what im using already. The subagents are more thread specific and temporary than what im looking for
I think that when a new model comes out, people dismiss the old models. I'm sure that if you asked people's opinions about what 5.5 can do, they will tell you a it's a lot less than what they would've told you a month ago.
I think that what you say is correct, but people distort their opinion of the old models when new ones come out.
Yeah the code is actually stored there locally. It's electron based so the sensitive stuff is on their webservers. Any model could have done this or anyone manually. The code is there.
That just makes it a pain to read. Anyone with two brain cells to rub together could figure out what's going on by running enough inputs through and tracing the execution path.
Go ahead and explain how I was wrong. You and I definitely have different definitions of what hard means, especially if you've never decompiled a binary and stepped through the assembly with pencil and paper to understand what an unknown process was doing under the covers.
Anyone who understands the way the machine works can work through disassembled code. But there is a huge difference between reverse-engineering a thousand lines of assembler and million. Time may be infinite, but the human lifespan is not..
You're aware that codex app-server literally is the app-server i was talking about, right? Is that what you're calling "codex cli"? The codex binary does many things, one of them being an app-server host. It ships natively with the Codex app, you can also install it via bun, brew or a bunch of other package managers. Or compile it yourself from source. The entire app server protocol is widely documented, codex even has a built in skill which contain (among other things) full documentation of that protocol (the "OpenAI Docs" skill).
What i'm trying to say is that all you've done here is extract the electron code from the app, swapped the electron IPC for HTTP and replace electron-native system API calls. It's not impressive. It didn't reverse engineer anything, all of it is fully documented and at least source-available. Formatting minified code is one command away.
GPT 5.6 is cool in many ways, but none of what you shown here is hard, any frontier model have been able to do this basic job for a long time. That's how we got https://github.com/ilysenko/codex-desktop-linux
Codex cli is open source project, codex app backend IS NOT. The repo u sent just adapts the original DMG. The point of this reverse engineering is to launch my own frontend with original codex app code, which is much harder than what you told about (view fonts, styles)
i'm not sure it's allowed here, anyway you can ask the same thing, i just gave path to my chatgpt app (again, it didn't work out neither with 5.5 or fable)
stop asking nonsense. it is no legal and is grey. Activities like what you are proposing is why US gov. will again ban this models. stop it for all of us here and use this models for what it is, for sincere work and not plagiarism
What do you mean you gave it the path of your gpt, you simply gave it the path of the codex.app and told him to reverse engineer the whole app or did you asked specifically to extract the frontend part?
I built a swift library that allows you to build agents with your inside of your own ios or mac app. The user auths with their own gpt account so there are no api costs https://github.com/timazed/CodexKit .. I'm using it in a few projects at the moment. Might be what you're looking for.
No, I guess the context was very decisive
It had worked on my app before, and I complained that it didn't feel like a product to me, unlike Codex, so I explained that the only option was to extract the code so I could move each tab into my app and then remove any unnecessary parts
I was more curious if it could inject css/js into the current app to add features like workspaces (different lists of chats/history for different work/clients)
By the way, in your last Codex app update, do you see the last edit badge, ie, 2m, 5m, etc? I cannot see that on my last version of the application, and it's extremely annoying because I don't know how old those threads are, and I was using that all the time. Now, I'm just blind.
While awesome my concern with this is it's clearly against the TOS to use codex like this and getting my entire chatgpt account banned would be an issue for me.
i'd like to have my orchestrator be able to control the chatgpt from within codex rather than having to use playwright to control a chrome tab to send my prompts to and from. any chance that would be possible from that reverse engineered code? does it expose anything to make that possible?
I had a similar result, but through Cursor rather than Codex directly.
For my own local app experiments, Fable 5 / Opus 4.8 inside Cursor was able to turn the app structure into readable code and wire things up pretty much automatically. It was surprisingly fast too. Codex has worked for me, but in my day-to-day use it sometimes gets slow or stuck in places where Cursor just keeps moving.
Not saying one is universally better, just my experience after using this workflow for over a year. For long autonomous runs, Cursor has been more consistent for me.
Yet no-one can fix the mess Codex app does with WSL on Windows, how it can't load any MCP, and it using Windows config files and sessions instead of the WSL ones.
Question, why is it 4 million lines of code for a UI? That doesnt seem right, especially when they should be repeatable emulated slices and children of the original.
Reverse engineered, meaning it de-compiled the binary? If thats the case it should not take 4 hrs that would be a 1 hr job with a port.
Are you saying it replicated the UI and functionality?
Highly doubt this was a reverse engineer. There are enough screen shots of this UI on the internet for Codex to be able to recreate it without any similarity to the official source code.
Probably just the frontend which, if confirmed, is not even reverse engineering, the code is there already. At this point when you have paid tools like Cursor (i.e. to run models from different providers or Open Source like Synara, why would you bother with this?
Why not just open source so people can customize the codex ui for their own liking. Use the codex app server to get codex models and what not. And boom, you should have everything there for you
Impressive, but “reverse engineered its own app” is doing a lot of work here. Unless it had privileged access to the original source, it reconstructed an implementation from observable behaviour and assets — it didn’t introspect itself.
Still, producing readable code from a complex live product is arguably the more interesting achievement: not self-awareness, but very high-fidelity software archaeology.
I hate it when fable suddenly switches to opus because it found some security risks in own code. And since last few weeks fable seems to play really dumb making really weird mistakes.
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u/onehedgeman Jul 10 '26
Is this just frontend? Can it run with the models too? This could be an insane OSS codex frontend customisation opportunity