OpenAI launches GPT-5.3-Codex, which it says runs 25% faster, enabling longer-running tasks, and “is our first model that was instrumental in creating itself”

ZDNET's key takeaways — GPT-5.3-Codex helped debug and deploy parts of itself. — Codex can be steered mid-task without losing context.

ZDNET 2026-02-06 David Gewirtz

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@sama Sam Altman on x
This is our first model that hits “high” for cybersecurity on our preparedness framework. We are piloting a Trusted Access framework, and committing $10 million in API credits to accelerate cyber defense. https://openai.com/...
@sama Sam Altman on x
I love building with this model; it feels like more of a step forward than the benchmarks suggest. Also you can choose “pragmatic” or “friendly” for its personality; people have strong preferences one way or the other!
@scaling01 @scaling01 on x
GPT-5.3 Codex absolutely demolished Opus 4.6 (65.4%) on Terminal Bench 2 just minutes after its launch! [image]
@gdb Greg Brockman on x
Software development is undergoing a renaissance in front of our eyes. If you haven't used the tools recently, you likely are underestimating what you're missing. Since December, there's been a step function improvement in what tools like Codex can do. Some great engineers at …
@marvinvonhagen Marvin von Hagen on x
“GPT-5.3-Codex is our first model that was instrumental in creating itself.”
@sama Sam Altman on x
GPT-5.3-Codex is here! *Best coding performance (57% SWE-Bench Pro, 76% TerminalBench 2.0, 64% OSWorld). *Mid-task steerability and live updates during tasks. *Faster! Less than half the tokens of 5.2-Codex for same tasks, and >25% faster per token! *Good computer use.
@embirico Alexander Embiricos on x
GPT-5.3-Codex is out! State of the art of SWEBench Pro and TBench, and a big leap in how it _feels_: - Mid-turn updates tell you what it's doing - Steer without interrupting - 25% faster via inference improvements I've been loving it. Think you will too https://openai.com/... [vi…
@dimillian Thomas Ricouard on x
I've been playing with GPT-5.3-Codex for a while, and let me tell you, this is simply the best model I've used (of course). But basically, going back to anything before is a big downgrade. It's straight to the point, fast, and also chatty with its new multi-turn feedback loop. [i…
@natolambert Nathan Lambert on x
“Due to GPT-5.3-Codex being so different from its predecessors, the data from alpha testing exhibited numerous unusual and counter-intuitive results” Sounds worth giving a go. Big changes are good.
@sarahwooders Sarah Wooders on x
Not available on the API in the name of “safety” (classic OpenAI), so impossible to properly evaluate or try out I'll be sticking to Opus 4.6 [image]
@scaling01 @scaling01 on x
OpenAI released GPT-5.3-Codex with massive improvements in reasoning efficiency! [image]
@openaidevs @openaidevs on x
GPT-5.3-Codex is our first model that was instrumental in creating itself. The Codex team used early versions to debug training, manage deployment, and diagnose test results and evaluations, accelerating its own development.
@gdb Greg Brockman on x
gpt-5.3-codex — smarter, faster, and very capable at tasks like making presentations, spreadsheets, and other work products. Codex becoming an agent that can do nearly anything developers and professionals can do on a computer. [image]
@zephyr_z9 @zephyr_z9 on x
Need more speed ups like this to enable long horizon tasks and not bore the user to death
@sama Sam Altman on x
It was amazing to watch how much faster we were able to ship 5.3-Codex by using 5.3-Codex, and fore sure this is a sign of things to come.
@youjiacheng You Jiacheng on x
5.3 only uses 48% tokens of 5.2 (both xhigh) and has 25% higher TPS. the wallclock speedup is +160% (2.6× speed), crazy.
@badlogicgames Mario Zechner on x
Ok, After 2 hours of working with Codex 5.3, I can't really say that it's smarter. It is faster, but that seems to be about it. Makes the same dumb mistakes as 5.2 in the same codebase. All just vibes.
@badlogicgames Mario Zechner on x
Vibeservations on Codex 5.3: - Faster - Sticks to https://agents.md/ better (goes into system prompt). E.g. previously, it would not run tests it modified/created. Now it does as per https://agents.md/. Yay. [image]
@sergeykarayev Sergey Karayev on x
GPT 5.3 Codex is ABSOLUTELY INCREDIBLE on our “personal SWE-Bench”, which is based on gold standard PRs into our Ruby on Rails codebase. Opus 4.6 is a tiny bit better than 4.5 but very underwhelming overall. Will see if the vibes match the bench! More about the benchmark: [image]
@synthwavedd Leo on x
THEY RELEASED 5.3 CODEX THE SECOND OPUS 4.6 DROPPED LMAO [image]
@danielkarunaa Daniel on x
aaaaand gpt-5.3-codex in codex cli now! great timing (v0.98.0) [image]
@nvidianewsroom @nvidianewsroom on x
OpenAI's new GPT-5.3-Codex was co-designed for, trained with, and is served on NVIDIA GB200 NVL72 systems, accelerating the frontier of AI. We're excited to see what developers build next with this breakthrough in code intelligence.
@kimmonismus @kimmonismus on x
GPT-5.3 codex!! What a day!!
@timkellogg.me Tim Kellogg on bluesky
GPT-5.3-Codex — Cheaper (fewer tokens, higher intelligence) — you can interrupt it — big focus on coding — first LLM to be used extensively in its own development — openai.com/index/introd... [image]
r/singularity r on reddit
OpenAI released GPT 5.3 Codex
r/accelerate r on reddit
GPT-5.3 Codex is out now, minutes after Opus 4.6
@sama Sam Altman on x
The 5.3 lovefest is so nice to see. Don't think we've had so much excitement for a model since the original GPT-4.
@davis7 Ben Davis on x
GPT-5.3 Codex is a massive improvement over 5.2 holy shit Way faster, fewer tool calls, and a more accurate result... [image]
r/OpenAI r on reddit
“GPT-5.3-Codex is our first model that was instrumental in creating itself.”

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OpenAI launches GPT-5.3-Codex, which it says runs 25% faster, enabling longer-running tasks, and “is our first model that was instrumental in creating itself”

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