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GPT-5.3-Codex

Whats interesting to me is that these gpt-5.3 and opus-4.6 are diverging philosophically and really in the same way that actual engineers and orgs have diverged philosophically

With Codex (5.3), the framing is an interactive collaborator: you steer it mid-execution, stay in the loop, course-correct as it works.

With Opus 4.6, the emphasis is the opposite: a more autonomous, agentic, thoughtful system that plans deeply, runs longer, and asks less of the human.

that feels like a reflection of a real split in how people think llm-based coding should work...

some want tight human-in-the-loop control and others want to delegate whole chunks of work and review the result

Interested to see if we eventually see models optimize for those two philosophies and 3rd, 4th, 5th philosophies that will emerge in the coming years.

Maybe it will be less about benchmarks and more about different ideas of what working-with-ai means

by Rperry21741770321686
I think Anthropic rushed out the release before 10am this morning to avoid having to put in comparisons to GPT-5.3-codex!

The new Opus 4.6 scores 65.4 on Terminal-Bench 2.0, up from 64.7 from GPT-5.2-codex.

GPT-5.3-codex scores 77.3.

by granzymes1770315159
Something that caught my eye from the announcement:

> GPT‑5.3‑Codex is our first model that was instrumental in creating itself. The Codex team used early versions to debug its own training

I'm happy to see the Codex team moving to this kind of dogfooding. I think this was critical for Claude Code to achieve its momentum.

by itay-maman1770317776
,,GPT‑5.3-Codex is the first model we classify as High capability for cybersecurity-related tasks under our Preparedness Framework , and the first we’ve directly trained to identify software vulnerabilities. While we don’t have definitive evidence it can automate cyber attacks end-to-end, we’re taking a precautionary approach and deploying our most comprehensive cybersecurity safety stack to date. Our mitigations include safety training, automated monitoring, trusted access for advanced capabilities, and enforcement pipelines including threat intelligence.''

While I love Codex and believe it's amazing tool, I believe their preparedness framework is out of date. As it is more and more capable of vibe coding complex apps, it's getting clear that the main security issues will come up by having more and more security critical software vibe coded.

It's great to look at systems written by humans and how well Codex can be used against software written by humans, but it's getting more important to measure the opposite: how well humans (or their own software) are able to infiltrate complex systems written mostly by Codex, and get better on that scale.

In simpler terms: Codex should write secure software by default.

by xiphias21770316459
I've always been fascinated to see significantly more people talking about using Claude than I see people talking about Codex.

I know that's anecdotal, but it just seems Claude is often the default.

I'm sure there are key differences in how they handle coding tasks and maybe Claude is even a little better in some areas.

However, the note I see the most from Claude users is running out of usage.

Coding differences aside, this would be the biggest factor for me using one over the other. After several months on Codex's $20/mo. plan (and some pretty significant usage days), I have only come close to my usage limit once (never fully exceeded it).

That (at least to me) seems to be a much bigger deal than coding nuances.

by SunshineTheCat1770324493
I remember when AI labs coordinated so they didn't push major announcements on the same day to avoid cannibalizing each other. Now we have AI labs pushing major announcements within 30 minutes.
by minimaxir1770315033
I've been listening to the insane 100x productivity gains you all are getting with AI and "this new crazy model is a real game changer" for a few years now, I think it's about time I asked:

Can you guys point me ton a single useful, majority LLM-written, preferably reliable, program that solves a non-trivial problem that hasn't been solved before a bunch of times in publicly available code?

by nananana91770321044
Terminal Bench 2.0

  | Name                | Score |
  |---------------------|-------|
  | OpenAI Codex 5.3    | 77.3  |
  | Anthropic Opus 4.6  | 65.4  |
by tosh1770317168
> Using the develop web game skill and preselected, generic follow-up prompts like "fix the bug" or "improve the game", GPT‑5.3-Codex iterated on the games autonomously over millions of tokens.

I wish they would share the full conversation, token counts and more. I'd like to have a better sense of how they normalize these comparisons across version. Is this a 3-prompt 10m token game? a 30-prompt 100m token game? Are both models using similar prompts/token counts?

I vibe coded a small factorio web clone [1] that got pretty far using the models from last summer. I'd love to compare against this.

[1] https://factory-gpt.vercel.app/

by bgirard1770320980
I would love to see a nutritional facts label on how many prompts / % of code / ratio of human involvement needed to use the models to develop their latest models for the various parts of their systems.
by textlapse1770327575
When 2 multi billion giants advertise same day, it is not competition but rather a sign of struggle and survival. With all the power of the "best artificial intelligence" at your disposition, and a lot of capital also all the brilliant minds, THIS IS WHAT YOU COULD COME UP WITH?

Interesting

by trilogic1770315795
The behind the scenes on deciding when to release these models has got to be pretty insanely stressful if they're coming out within 30 minutes-ish of each other.
by morleytj1770317049
Using opus 4.6 in claude code right now. It's taking about 5x longer to think things through, if not more.
by dllrr1770323028
Both Opus 4.6 and GPT-5.3 one shot a Gameboy emulator for me. Guess I need a better benchmark.
by gallerdude1770322549
> our team was blown away > by how much Codex was able > to accelerate its own development

they forgot to add “Can’t wait to see what you do with it”

by ffitch1770317711
> GPT‑5.3-Codex was co-designed for, trained with, and served on NVIDIA GB200 NVL72 systems. We are grateful to NVIDIA for their partnership.

This is hilarious lol

by kingstnap1770315764
For those who cared:

GPT-5.3-Codex dominates terminal coding with a roughly 12% lead (Terminal-Bench 2.0), while Opus 4.6 retains the edge in general computer use by 8% (OSWorld).

Anyone knows the difference between OSWorld vs OSWorld Verified?

by karmasimida1770320727
Do software engineers here feel threatened by this? I certainly am. I'm surprised that this topic is almost entirely missing in these threads.
by RivieraKid1770325973
AI designed websites are so easy to spot that I need to actively design my UI so that it doesn't look AI
by vatsachak1770326658
I want to recompile a Rust project to be f32 instead of f64.

Am I better off buying 1 month of Codex, Claude, or Antigravity?

I want to have the agent continuesly recompile and fix compile errors on loop until all the bugs from switching to f32 are gone.

by koolala1770324171
Did they post the knowledge cutoff date somewhere
by prng20211770317328
I think models are smart enough for most of the stuff, these little incremental changes barely matter now. What I want is the model that is fast.
by ponyous1770317823
I'm having a hard time parsing the openai website.

Anyone know if it is possible to use this model with opencode with the plus subscription?

by tyfon1770319230
Gotta love how the game demo's page title is "threejs" – I guess the point was to demo its vibe-coding abilities anyway, but yea..
by jdthedisciple1770317325
Anthropic mostly had an advantage in speed. It feels like with a 25% increase in speed with Codex 5.3, they are now losing that advantage as well.
by Robin_f1770316071
I never really used Codex (found it to slow) just 5.2, which I going to be an excellent model for my work. This looks like another step up.

This week, I'm all local though, playing with opencode and running qwen3 coder next on my little spark machine. With the way these local models are progressing, I might move all my llm work locally.

by __mharrison__1770317689
It's so difficult to compare these models because they're not running the same set of evals. I think literally the only eval variant that was reported for both Opus 4.6 and GPT-5.3-Codex is Terminal-Bench 2.0, with Opus 4.6 at 65.4% and GPT-5.3-Codex at 77.3%. None of the other evals were identical, so the numbers for them are not comparable.
by modeless1770316457
Interesting that this was released without a prior GPT-5.3 release. I wonder if that means we won't see a GPT-5.3?
by jpau1770323678
I find it very, very interesting how they demoed visuals in the form of the “soft SaaS” website and mentioned how it can do user research. Codex has usually lagged behind Claude and Gemini when it comes to UX, so I’m curious to see if 5.3 will take the lead in real world use. Perhaps it’ll be available in Figma Make now?
by GenerWork1770316601
gpt-5.3-codex isn't available on the API yet. From TFA:

> We are working to safely enable API access soon.

by gwd1770317405
May AI not write the code for me.

May I at least understand what it has "written". AI help is good but don't replace real programmers completely. I'm enough copy pasting code i don't understand. What if one day AI will fall down and there will be no real programmers to write the software. AI for help is good but I don't want AI to write whole files into my project. Then something may broke and I won't know what's broken. I've experienced it many times already. Told the AI to write something for me. The code was not working at all. It was compiling normally but the program was bugged. Or when I was making some bigger project with ChatGPT only, it was mostly working but after a longer time when I was promting more and more things, everything got broken.

by dawidg811770318567
GPT-5.2-Codex was so cool at price/value rate, hope 5.3 will not ruin the race with claude
by imasliev1770316814
Having used codex a fair bit I find it really struggles with … almost anything. However using the equivalent chat gpt model is fantastic. I guess it’s a matter of focus and being provided with a smaller set of code to tackle.
by foft1770317698
That was fast!

I really do wonder whats the chain here. Did Sam see the Opus announcement and DM someone a minute later?

by kingstnap1770315452
Anyone remember the dot-com era when you would see one provider claim the most miles of fibre and then later that week another would have the title?
by rustyhancock1770318559
is so fun that the two releases used almost completely non-overlapping benchmarks!
by virtualzx1770326194
Funny that this and Opus 4.6 released within minutes of each other. Each showing similar score improvements. Each claiming to be revolutionary.
by ecshafer1770317629
I've been using 5.2 the way they're describing the new use case for 5.3 this whole time.
by davidmurdoch1770319207
How'd they both release at the same time? Insiders?
by PieUser1770321282
by 1770315344
At first try it solved a problem that 5.2 couldn't previously.

Seems to be slower/thinks longer.

by binsquare1770316381
The most important question: Can it do Svelte now?
by bryanhogan1770319168
So can I use this from Opencode? Because Anthropic started to enforce their TOS to kill the Opencode integration
by edem1770315818
Where is the google?
by kopollo1770318073
by 1770316225
Any notes on pricing?
by simianwords1770315696
According to Sam Altman, Anthropic is for "rich people." Judging by his $4 million man-baby Koeniggsegg, he must be a huge Claude Code user!
by mrcwinn1770325725
I am on a max subscription for Claude, and hate the fact that OpenAI have not figured out that $20 => $200 is a big jump. Good luck to them. In terms of model, just last night, Codex 5.2 solved a problem for me which other models were going round and round. Almost same instructions. That said, I still plan to be on $100 Claude (overall value across many tasks, ability to create docs, co-work), and may bump up OpenAI subscription to the next tier should they decide to introduce one. Not going to $200 even with 5.3, unless my company pays for it.
by bg241770319036
Does it insert adverts in your code?
by drcongo1770325064
It seems Fast!
by maheshrijal1770315458
I'd like to know if and how much illegal use of customer prompts are used for training.
by I_am_tiberius1770316913
Whoa, I think GPT-5.2-Codex was a disappointment, but GPT-5.3-Codex is definitely the future!
by petetnt1770325037
what are the benchmarks against opus 4.6?
by roya517881770317775
Anybody else not seeing it available in Codex app or CLI yet (with Plus)?
by hubraumhugo1770317867
Anthropic and GTP 2 new models at once?
by heraldgeezer1770317155
Pelican seems much worse than the Opus 4.6 one (though the bicycle is more accurate):

https://gist.github.com/simonw/a6806ce41b4c721e240a4548ecdbe...

by wahnfrieden1770316929
It is absurd to release 5.3-Codex before first releasing 5.3.

Also, there is no reason for OpenAI and Anthropic to be trying to one-up each other's releases on the same day. It is hell for the reader.

by OutOfHere1770316389
lmao so cringe that they delay releasing the model until anthropic does
by nubg1770322769
Almost like Anthropic and OpenAI are trying to front run each other
by raincole1770315431
[dead]
by copilot_king1770316728
[flagged]
by xyst1770325335
[flagged]
by mannanj1770316485
[flagged]
by copilot_king_21770316455
I know we just got a reset and a 2× bump with the native app release, but shipping 5.3 with no reset feels mismatched. If I’d known this was coming, I wouldn’t have used up the quota on the previous model.
by shibeprime1770315783
Is this me or Sam is being absolute sore loser he is and trying to steal Opus thunder?
by maxpert1770316275