GPT-5-Codex
24 comments
·September 15, 2025jumploops
siva7
So you're all saying suddenly codex cli w gpt 5 codex is better than claude code? Hard to believe
tedsanders
> SWE-bench performance is similar to normal gpt-5, so it seems the main delta with `gpt-5-codex` is on code refactors
SWE-bench is a great eval, but it's very narrow. Two models can have the same SWE-bench scores but very different user experiences.
Here's a nice thread on X about the things that SWE-bench doesn't measure:
dwaltrip
so annoying you cant read replies without an account nowadays
pants2
Interestingly, "more steerable" can sometimes be a bad thing, as it will tend to follow your prompt to the letter even if that's against your interests. It requires better prompting and generally knowing what you're doing - might be worse for vibe-coders and better for experienced SWEs.
htrp
think they're indexing here for professional work (people in the VSCode terminal)
robotswantdata
Codex CLI IDE just works, very impressed with the quality. If you tried it a while back and didn’t like it, try it again via the vscode extension generous usage included with plus.
Ditched my Claude code max sub for the ChatGPT pro $200 plan. So much faster, and not hit any limits yet.
steinvakt2
Im using Cursor with the $20 plan and hit rate limits after 15 days (so im paying extra the rest of the month). What do you recommend I do?
robotswantdata
You could get two plus accounts? Or maybe a business account with two seats?
The $200 pro feels good value personally.
poszlem
Wait, what? They now allow claude code like subscription instead of the API too?
Tiberium
Yes, just do "codex login" and it'll use your ChatGPT subscription.
robotswantdata
Yes for at least a month. Download the vscode extension and sign in with ChatGPT
Tiberium
Only an 1.7% upgrade on SWE-Bench compared to GPT-5, but 33.9 vs 51.3% on their internal code refactoring benchmark. This seems like an Opus 4.1-like upgrade, which is nice to see and means they're serious about Codex.
ianbutler
I just want the codex models in the API, I won’t touch them until then.
And before someone says it, I do happen to have my own codex like environment complete with development containers, browser, github integration, etc.
And I'm happy to pay a mint for access to the best models.
alvis
It's interest to see this quote: `for the bottom 10% of user turns sorted by model-generated tokens (including hidden reasoning and final output), GPT‑5-Codex uses 93.7% fewer tokens than GPT‑5`
It sounds like it can make simple tasks much more correct. It's impressive to me. Today coding agent tends to pretend they're working hard by generating lots of unnecessary code. Hope it's true
bn-l
This is my issue with gpt-5. If you use the low or medium reasoning it’s garbage. If you use high, it’ll think for up to five minutes on something dead simple.
trilogic
Is so good that need advertising, LOL. (Anthropic enters chat)... Jokes apart, I guess it is good (cause I cant afford it to try). (Meta enters chat)... Deepseek R2 enters chat and drop mike. Anthtopic, Meta, OpenAi, Google, leaves chat and call Trump for another Dinner.
No really Jokes apart, ChatGPT and Trump are awesome, all works and keeps getting better by the day.
Topfi
One major improvement I have seen today, even before I saw the announcement, was that the model is far more reliable in using the Task Completion interface to communicate what stage of the prompt is being implemented. Previously this was only shown sparingly (especially in the first few weeks) and if, it didn't properly tick tasks, simply jumping from the first to completion at the end. Now this works very reliably and I do like this improvement, but if I didn't know better, would have suspected this was merely the result of a system prompt change, considering GPT-5 adherence being very solid in my experience, this should have been fixable without a tuned model. Nevertheless, I like this improvement (arguably fix of a previously broken feature).
Beyond that, purely anecdotal and subjective, but this model does seem to do extensive refactors with semi precise step-by-step guidance a bit faster (comparing GPT-5 Thinking (Medium) and GPT-5 Codex (Medium)), though adherence to prompts seems roughly equivalent between the two as of now. In any case, I really feel they should consider a more nuanced naming convention.
New Claude Sonnet 3.7 was a bit of a blunder, but overall, Anthropic has their marketing in tight order compared to OpenAI. Claude Code, Sonnet, Opus, those are great, clear differentiating names.
Codex meanwhile can mean anything from a service for code reviews with Github integration to a series of dedicated models going back to 2021.
Also, while I do enjoy the ChatGPT app integration for quick on-the-go work made easier with a Clicks keyboard, I am getting more annoyed by the drift between Codex VSCode, Codex Website and Codex in the ChatGPT mobile app. The Website has a very helpful Ask button, which can also be used to launch subtasks via prompts written by the model, but such a button is not present in the VSCode plugin, despite subtasks being something you can launch from the VSCode plugin if you have used Ask via the website first. Meanwhile, the iOS app has no Ask button and no sub task support and neither the app, nor VSCode plugin show remote work done beyond abbreviations, whereas the web page does show everything. Then there are the differences between local and remote via VSCode and the CLI, ... To people not using Codex, this must sound insane and barely understandable, but it seems that is the outcome of spreading yourself across so many fields. CLI, dedicated models, VSCode plugin, mobile app, code review, web page, some like Anthropic only work on one or two, others like Augment three, but no one else does that much, for better and worse.
I like using Codex, but it is a mess with such massive potential that needs a dedicated team lead whose only focus is to untangle this mess, before adding more features. Alternatively, maybe interview a few power user on their actual day to day experience, those that aren't just in one, but are using multiple or all parts of Codex. There is a lot of insight to be gained from someone who has an overview off the entire product stack, I think. Sending out a questionnaire to top users would be a good start, I'd definitely answer.
j45
Has anyone hit any programming usage limits with the ChatGPT 5 Pro account?
incomingpain
Still waiting on codex cli to support lm studio.
NitpickLawyer
? Isn't lmstudio API openai compatible? Codex cli already supports 3rd party models, you have to edit the config yaml file, and you can add many model providers.
brador
Take off the guardrails and let humanity thrive.
It is inevitable.
Interesting, the new model's prompt is ~half the size (10KB vs. 23KB) of the previous prompt[0][1].
SWE-bench performance is similar to normal gpt-5, so it seems the main delta with `gpt-5-codex` is on code refactors (via internal refactor benchmark 33.9% -> 51.3%).
As someone who recently used Codex CLI (`gpt-5-high`) to do a relatively large refactor (multiple internal libs to dedicated packages), I kept running into bugs introduced when the model would delete a file and then rewrite in (missing crucial or important details). My approach would have been to just the copy the file over and then make package-specific changes, so maybe better tool calling is at play here.
Additionally, they claim the new model is more steerable (both with AGENTS.md and generally). In my experience, Codex CLI w/gpt-5 is already a lot more steerable than Claude Code, but any improvements are welcome!
[0]https://github.com/openai/codex/blob/main/codex-rs/core/gpt_...
[1]https://github.com/openai/codex/blob/main/codex-rs/core/prom...