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GPT-5-Codex

openai.com

396 pointsmeetpateltech137 comments

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...

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.

think they're indexing here for professional work (people in the VSCode terminal)

Yes, given a similarly sparse prompt, Claude Code seems to perform "better" because it eagerly does things you don't necessarily know to ask

GPT-5 may underwhelm with the same sparse prompt, as it seems to do exactly what's asked, not more

You can still "fully vibe" with GPT-5, but the pattern works better in two steps:

1. Plan (iterate on high-level spec/PRD, split into actions)

2. Build (work through plans)

Splitting the context here is important, as any LLM will perform worse as the context gets more polluted.

The best of both worlds would surely be for the LLM to write what you've asked, but also write comments about other things it could have done so you can consider those extra bits when you check the output.

I've found if you prompt a persona with these expectations GPT is pretty good at honoring it.

> 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:

https://x.com/brhydon/status/1953648884309536958

so annoying you cant read replies without an account nowadays

Use Nitter, the main instance works but there are a lot of other instances as well.

https://nitter.net/brhydon/status/1953648884309536958

Change the url from x.com to xcancel.com to see it all.

So you're all saying suddenly codex cli w gpt 5 codex is better than claude code? Hard to believe

Not suddenly, it's been better since GPT-5 launched.

Prompting is different, but in a good way.

With Claude Code, you can use less prompting, and Claude will get token happy and expand on your request. Great for greenfield/vibing, bad for iterating on existing projects.

With Codex CLI, GPT-5 seems to handle instructions much more precisely. It won't just go off on it's own and do a bunch of work, it will do what you ask.

I've found that being more specific up-front gets better results with GPT-5, whereas with Claude, being more specific doesn't necessarily stop the eagerness of it's output.

As with all LLMs, you can't compare apples to oranges, so to clarify, my experiences are primarily with Typescript and Rust codebases.

Codex CLI of course will sometimes do the wrong thing, or sometimes do something extra that you didn't intend for it to do.

It seems about half my sessions quickly become "why did you do that? rip __ out and just do ___". Then again, most of the other sessions involve Codex correctly inferring what I wanted without having to be so specific.

Yeah, I tried Claude Code CLI and never found it too useful, but that was Claude 3.5 era. Still using Claude 3.7/4.0 via Cursor were much better but still had to micro managed.

GPT5 + Codex CLI has been pretty productive for me. It's able to get a lot right in a simple prompt without getting too distracted with other crap. It's not perfect, but it's pretty good.

I actually worry GPT5-Codex will make it worse on that aspect though. One of the best parts of GPT5/Codex CLI is that it tends to plan and research first, then make code.

Sounds like the difference between finding what needs to be done, making a plan, and executing on it remains something to consider and be aware of.

Claude Code has been a revelation and a bit of a let down the past 45 days.

Some open acknowledgement would have been great, but in lieu of it, it seems it's best to hop on a new tool and make sure you learn how to prompt better and not rely on the model to read between until usage is "optimized" and it no longer seems to work for those folks.

I've seen some interesting files that help any model understand a programming language as it's strong suit and it might not even be an expert in and how to best develop with it.

Anthropic acknowledged there were bugs that are now resolved, see their status page for latest info:

https://status.anthropic.com/

The models themselves are responding differently to prior chat requests being run again.

Yea, I have struggled with Claude to keep it focused on what I want and only what I want. I have no experience with GPT-5-Codex, but maybe I should.

This has been my experience even in Cursor. I often select the GPT-5 option because I know it will "know" better how much reasoning effort it needs

So is gpt-5-codex-high better than gpt-5-high? I find it hard to believe that with half the instruction tokens a MOE model could significantly outperform, but I am certainly not knowledgable in fine-tuning.

It is 100% true. And they are rapidly losing users to Codex. Charts were shared recently showing a massive migration underway.

Oh yeah, Sonnet performance has been in the toilet for me. They claim they've mitigated it but when 4.0 first dropped CC was really impressive, and now I constantly have to babysit it because any time it hits a challenge it'll just stop trying and make a simple toy version and declare false victory. If I don't catch it and I let it build on top of that bullshit, things get nasty in a hurry.

It's a shame because the plan is a great deal but the number of all caps and profanity laced messages I'm firing off at Claude is too damned high.

GPT-5 is comparable to Opus without needing to constantly dip back down to Sonnet for cost management

Yes, this. I feel like I’m going crazy. I pay for the extra Opus usage and I keep checking the model switcher to see if it has automatically switched to Sonnet. It has not. I just have a lot more experiences of it feeling anecdotally dumb lately.

This hits home for me too. Claude feels like it has gotten more "yes-man"-y. I can no longer trust its judgement. Even if I come in with something dead wrong, I'm "absolutely right" and it finds amazing ways to spin my BS into something vaguely believable.

I am also bullying Claude more nowadays. Seeing this thread, I might give Codex another go (I was on Codex CLI before Claude Code. At that time, Claude blew Codex out of the water but something's changed)

Am I missing something? That.. doesn't seem to be true? https://npmtrends.com/@anthropic-ai/claude-code-vs-@openai/c...

Its been better for awhile, people are sleeping on it, just like they slept on claude code when it initially came out.

People are using claude code + glm models as alternative too, some complaints flying around.

Small suggestion on refactors into packages: Move the files manually. Just tell codex "they used to be in different locations, fix it up so it builds".

It seems that the concept of file moving isn't something Codex (and other clis) handle well yet. (Same goes for removing. I've ~never seen success in tracking moves and removes in the git commit if I ask for one)

Does refactoring mean moving things around for people? Why don't you use your IDE for this, it already handles fixing imports (or use find-replace) and it's faster and deterministic.

Not necessarily -- in the case I posted about, we first abstracted some common functionality to internal libs, and then further abstracted that functionality into a number of packages (so they could be used by other clients).

So it was part simplification (dedupe+consolidate), and part moving files around.

Not always, but since OP mentioned it was "deleting and rewriting" files - that's how the CLI agents usually "move" files.

And sure, you can use an IDE, but that's harder to do if you live in vibe land. (We really need to understand that for some things, we have perfectly fine non-AI answers, but that's not the world as it is right now. Mechanical refactors, move + import fixes, autocomplete - all of those do not require an LLM. We're not great at drawing that line yet)

I wonder if this means part of the prompt has been moved to a higher level somehow... or baked into the bread elsewhere.

I've been a hardcore claude-4-sonnet + Cursor fan for a long time, but in the last 2 months my usage went through the roof. I started with the basic Cursor subscription, then upgraded to pro, until I hit usage limits again. Then I started using my own Claude API key but I was still paying ~70$ / 5 days, which is not that sustainable for me. But since grok-code-fast-1 landed, I've been using it daily with Cursor and it's fantastic, fast and cheap (free so far). I've also been using GPT-5 lately through the official Codex VSCode extension, and it blows my mind. Last night I used gpt-5-medium to help me heavily refactor a react-native app, improved it's structure and overall performance, something that would've taken me at least 2 days. Now I'm testing out gpt-5-medium-codex, asked it to restructure the entire app routing, and it seems it makes a lot of tool calls, understands, executes commands, it's very organized. Overall my stack from now on is Cursor + grok-code-fast-1 for daily use, and Codex/GPT when I need the brainz. Worth noting that I abused gpt-5-medium all day long yesterday, and I never hit any kind of limit (I just used by ChatGPT Plus account), reason for which I thank the OpenAI team

What exactly did your work flow look like for the gpt-5-medium refactor you did?

I don't have a test like that on hand so I'm really curious what all you prompted the model, what it suggested, and how much your knowledge as a SWE enabled that workflow.

I'd like a more concrete understanding if the mind blowing nature is attainable for any average SWE, an average Joe that tinkers, or only a top decile engineer.

I also hit Cursor usage limits for the first time in a year. Hit limits on Claude, GPT, and then it started using Grok :)

I chose to turn on Cursor's pay per usage within the Pro plan (so I paid $25, $20+$5 usage, instead of upgrading to $60/m) in order to keep using Claude because it's faster than Grok

I've landed on more or less the same. grok-code-fast-1 has been working well for most coding tasks. I use it in opencode (I guess it's free for some amount of time? Because I haven't added any grok keys ¯\_(ツ)_/¯)

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.

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?

You could get two plus accounts? Or maybe a business account with two seats?

The $200 pro feels good value personally.

Wait, what? They now allow claude code like subscription instead of the API too?

Yes for at least a month. Download the vscode extension and sign in with ChatGPT

Yes, just do "codex login" and it'll use your ChatGPT subscription.

Do you also get free Codex CLI usage?

>CLI IDE

What?

Codex cli Vscode extension https://developers.openai.com/codex/ide

just drop the "cli" part of it?

Well, it's really a VSCode extension that lets you run Codex CLI in the IDE. Not the "cloud" version of Codex... So GP is technically correct

i just use aider + gemini pro, here's the project i developed: https://aretecodex.pages.dev/tools/

Did anybody switch away from Aider for a compelling alternative? What was the feature?

I still like aider but multi-step agentic flows are very useful so I mostly use codex and claude nowadays. If I want to do very specific edits I use aider.

I don't find multiple agents helpful at all for coding, here you can see i am running a modded aider and single shot most features, https://www.reddit.com/r/ChatGPTCoding/comments/1nh7bu1/3_ph...

I also use claude or codex but i do not find them much useful for what i do.

Where does regular Aider fall short?

bruh, i posted a video for you to see where it falls short. If you are an aider user you can tell based on video what it can or cannot do.

I was a #1 aider stan for months, but ultimately switched to Claude Code.

For me it was (1) lack of MCP (2) excessive hand-holding required (3) availability of the Max plan meant I wouldn't have to monitor cost.

Claude Code's skill curve felt slightly longer than aider's, and had a higher ceiling.

I think if I were more cost-sensitive, I would give Aider another whirl, or Gemini CLI (based on what I've heard, I haven't used it yet).

Why not Gemini CLI tho?

it sucks.

The opposite of my experience, but okay.

I'll give it another try, the gemini models themselves are great for me, tried the tool when it came out, didn't gel with it.

It doesn't have a working plan mode.

If you ask it to plan something or suggest something. It'll write the suggestion and dive right into implementation with zero hesitation.

It's not my experience, but then I have a „living” GEMINI.md doc where I add/clarify/tweak what to do and what not to do. And it's possible the initial revision already contained the correct spell :)

gemini cli is such a trash it has ruined gemini 2.5 pro model's reputation, now people think it's incapable of writing good code.

True. In my experience, it has been good to use for second opinions and code reviews. Usually in CC/Codex via an MCP like zen.

Do not let Gemini CLI write code for you. You will find out the hard way

From my observation of the past 2 weeks is that Claude Code is getting dramatically worse and super low usage quota's while OpenAI Codex is getting great and has a very generous usage quota in comparison.

For people that have not tried it in say ~1 month, give Codex CLI a try.

All that matters to the end users is to never be trapped. Cross-shop these products around constantly and go for lowest price, highest performance ratios. We've seen over the last year all companies trade blows, but none are offering something novel within the current space. There is no reason to "stick to one service". But the services will try very hard to keep you stuck for that SaaS revenue.

Does it still go "your project is using git, let me just YOLO stuff" on first startup?

My essentials for any coding agent are proper whitelists for allowed commands (you can run uv run <anything>, but rm requires approval every time) and customisable slash commands.

I can live without hooks and subagents.

> proper whitelists for allowed commands (you can run uv run <anything>, but rm requires approval every time)

This is a nearly impossible problem to solve.

uv run rm *

Sandboxing and limiting its blast radius is the only reliable solution. For more inspiration: https://gtfobins.github.io/

It's been interesting reading this thread and seeing that others have also switched to using Codex over Claude Code. I kept running into a huge issue with Claude Code creating mock implementations and general fakery when it was overwhelmed. I spent so much time tuning my input prompt just to keep it from making things worse that I eventually switched.

Granted, it's not an apples-to-apples comparison since Codex has the advantage of working in a fully scaffolded codebase where it only has to paint by numbers, but my overall experience has been significantly better since switching.

1) create plan in plan-mode

2) ask it to implement plan

That's the way to work with Claude.

Other systems don't have a bespoke "planning" mode and there you need to "tune your input prompt" as they just rush in to implementation by guessing what you wanted

Question, how do I get the equivalent of Claude's "normal mode" in Codex CLI?

It is super annoying that it either vibe codes and just edits and use tools, or it has a plan mode, but no in-between where it asks me whether it's fine it does a or b.

I'm not understanding why it lacks such a capability, why in the world would I want to choose between having to copy paste the edits or auto accept them by default...

Usually I give it a prompt that includes telling it to formulate a plan and not not do any coding until I approve. I will usually do several loops of that before I give it the instruction to go forward with the plan. I like to copy and paste the plan elsewhere because at times these LLM's can "forget" the plan. I usually do testing at each major milestone (either handed off to me or do builds/unit tests.)

Yeah, no way I'm doing copy pasting or allowing it to vibe it.

I want it to help me come up with a plan, execute and check and edit every single edit but with the UX offered by claude, Codex is simply atrocious, I regret spending 23 euros on this.

I see the visual studio code extension does offer something like this, but the UX/UI is terrible, doesn't OAI have people testing those things?

The code is unreadable in that small window[1], doesn't show the lines above/below, it doesn't have IDE tooling (can't inspect types e.g.).

https://i.imgur.com/mfPpMlI.png

This is just not good, that's the kind of AI that slows me, doesn't help at all.

Very impressive. I've been working on a shared background presence animation, and have been testing out Claude and Codex. (By shared presence, I mean imagine a page's background changing based on where everyone's cursor is)

Both were struggling yesterday, with Claude being a bit ahead. Their biggest problems came with being "creative" (their solutions were pretty "stock"), and they had trouble making the simulation.

Tried the same problem on Codex today. The design it came up with still felt a bit lackluster, but it did _a lot_ better on the simulation.

> Their biggest problems came with being "creative" (their solutions were pretty "stock")

LLM designed UIs will always look generic/stock if you don’t give it additional prompting because of how LLMs work - they’ve memorized certain design patterns and if you don’t specify what you want they will always default to a certain look.

Try adding additional UI instructions to your prompts. Tell it what color scheme you want, what design choices you prefer, etc. Or tell it to scan your existing app’s design and try to match it. Often the results will be much better this way.

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.

I literally tried out Codex for the first time this weekend, and the results were ... weird. It'll be interesting to see if it does things differently. (It was a super simple prompt, standing up a Rails app in Docker Compose with a home page and Devise; it hard-coded each file to create inside of the bootstrap.sh, instead of actually creating the files to begin with)

I’ve been using Claude Code ($20/month) for about two weeks now, and with one of the token usage monitors I can handle most of what I need. I also have the $20/month ChatGPT plan. I know I could try Codex CLI, but I’ve been hesitant since I’ve seen people suddenly hit the limit and get locked out for a week. The problem is that there’s no way to check usage. So I’m wondering if this update improves token usage management, or if there’s now a way to actually see our usage so we don’t end up tripping the limit without any warning.

Same setup as your. Started with codex 2 days ago on a large 3d engine project. Spend at least 20 hours prompting. One time I received a message. Try again in 4 minutes. I generally let Gemini create a prompt and then paste it inside codex. For example is asked gemeni to make a plan for a subdivided lod terrain render with shadow map functionality etc. It took codex almost an hour to execute it. Did an alright job. Quite impressed.

I bought chatgpt last month and I think that openai is doing things right now, mostly in the experience, for example it has a better voice mode than Claude's and I liked their new model names than the confusing ones they used to have, it simplified the whole thing. Also as a general assistant is better too, for comparison Claude for non code things is not that very good. And openai keep releasing tools and seems more reliable in their tools

The code review thing might be my favorite UX for AI based development. Largely stays out of your way and provides good comments.

I’m imagining if it can navigate the codebase and modify tests - like add new cases or break the tests by changing a few lines. This can actually verify if the tests were doing actual assertions and being useful.

Thorough reviewing like this probably benefits me the most - more than AI assisted development.

Oh since when Codex cli is now included as part of a ChatGPT plan? 99% sure that wasn't the case before. Time to try to use it for real.

It's relatively new - they enabled it ~1 month ago or something.

They added that around June 4th, here's the PR: https://github.com/openai/codex/pull/1212

I thought i would give this AI assisted coding another go, so have subscribed to ChatGPT to try out this new codex, but it just seems soooooo slooooow.

I just don't see how this can be considered productive - I am waiting 20 minutes staring at it "thinking" while it does trivial tasks on a virtually bare repo. I guess for async agents its not such a big deal if they are slow as molasses, as you can run dozens of them, but you need a structured codebase for that - and i am already hours in and haven't even gotten a skeleton.

I have read through all the docs, watched the video. It would be so much quicker just to write this code myself. What am I doing wrong? Is it just super slow because they are over capacity or is this just the current state of the art?

What I see most engineers do is parallelize. Have multiple agents work at the same time. It takes some time getting used to, but I think they are on to something.

There's even an article I read about this the other week, but I can't seem to find it ATM.

Right. The idea here is to kick of 3-8 or something tasks. They finish as you finish writing the next prompt. Then you go and review/test/merge the code from the first task, then another task finishes and you review/test/merge that code.

The challenge is that you have to be working on multiple work streams at once because so far Codex isn't great at not doing work you are doing in another task even if you tell it something like "class X will have a function that returns y"...it will go write that function most times.

I've found it really good for integration work between frontend and backend features where you can iterate on both simultaneously if the code isn't in the same codebase.

Also, for Codex this works best in the web ui because it actually uses branches, opens prs, etc. I think (though could be wrong) that locally with the CLI or IDE extension you might have to manually great git worktrees, etc.

Yeah I try to keep it away from overlapping it's work as much as possible. Using plan mode in claude or just telling codex to build a plan, that is structured in a parallelized way for multiple agents usually helps delegate tasks to be handled at the same time. Typically: app code, infra, and data layer are the main three, but obviously depends on the project.

If I ever find my self just waiting, then it always gives me an opportunity to respond to messages, emails, or update tickets. Won't be long now until the agents are doing that as well...

I can understand how you can parallelize tasks when there is some structure - but how do you get to that initially structured state where each agent isn't recreating the world to conflict with every other agent?

When i use that approach I end up merging one PR, then have to prod the others to fix themselves - resolving conflicts, removing duplicate code, etc - so it ends up slower than just running one agent at a time.

Like i said - maybe this is a problem on a bare repo? But if so, how are people vibe coding from scratch and calling themselves productive? I just don't get it.

Doesn't seem ready for prime-time. I'll be impressed when it actually installs.

npm ERR! code 1 npm ERR! path /usr/local/lib/node_modules/@openai/codex/node_modules/@vscode/ripgrep npm ERR! command failed npm ERR! command sh -c node ./lib/postinstall.js npm ERR! /usr/local/lib/node_modules/@openai/codex/node_modules/@vscode/ripgrep/lib/download.js:199 npm ERR! zipFile?.close();

codex cli has been out for 5 months with 170k weekly downloads - it's definitely 'ready for primetime' if you can get past your bug. I don't have that issue.

The install errors out after following two basic install commands. This is poor code hygiene on the part of the authors. That's "not ready for primetime" in my book.

  npm ERR! code 1
  npm ERR! path /usr/local/lib/node_modules/@openai/codex/node_modules/@vscode/ripgrep
  npm ERR! command failed
  npm ERR! command sh -c node ./lib/postinstall.js
  npm ERR! /usr/local/lib/node_modules/@openai/codex/node_modules/@vscode/ripgrep/lib/download.js:199
  npm ERR!                     zipFile?.close();
  npm ERR!                             ^
  npm ERR! 
  npm ERR! SyntaxError: Unexpected token '.'

Please tell me you are not running a NodeJS release that hasn't been supported for at least 3 years...

Optional chaining was added in v14 (2020), and it sure looks like that is the issue here.

Brand new, clean install of npm.

Poor code + doc hygiene is the problem here.

The question is which version of node, not npm.

It doesn't matter. The install was broken as was written. That's poor hygiene.

It does matter.

Why yes, you're right, poor code hygiene and poor documentation hygiene does matter. We finally agree.

this should resolve that for you:

unset GITHUB_TOKEN

npm install --global @openai/codex

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

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.

Can you be more specific about what type of code you're talking about, and what makes it garbage?

I'm happy with medium reasoning. My projects have been in Go, Typescript, React Dockerfiles stuff like that. The code almost always works, it's usually not "Clean code" though.

Cool upgrade, but I wonder how this plays with existing tools like Copilot and Cursor. Everyone’s moving toward “AI pair programmer in every IDE,” and it feels like the competition is less about raw model quality now and more about integration + workflow lock-in. Codex getting everywhere (terminal, GitHub, phone) sounds powerful

I don't know. Something that takes CC about a minute is now on minute 15 with this new model...

I've considered swapping to Claude since the last update made talking to gpt absolutely terrible. I heavily make use of being able to put in PRs on mobile by working with codex, and if it wasn't for this I'd probably have switched. Excited to see the updates.

Don't. Claude is worse for everything but coding, and even then it's mostly better for coding in greenfield/small projects, and it makes a mess of large projects. The only thing really good about Claude was the plan economics, and now I'm not so sure about it.

It only makes a mess of large projects if your CLAUDE.md and docs/ are out of date.

It has a very specific style and if your project isn't in that style, it starts to enforce it -> "making a mess".

Nah bro. I have a Claude Code hall of shame, where Sonnet gets derailed by the most trivial shit, and instead of finishing actual research code that's been clearly outlined for it (like, file by file level instructions), it creates a broken toy implementation with fake/simulated output ("XXX isn't working, the user wants me to YYY, let me just try a simpler approach...") and it'll lie about it in the final report, so if you aren't watching the log, sucks to be you.

I have an extensive array of tripwires, provenance chain verifications and variance checks in my code, and I have to treat Claude as adversarial when I let it touch my research. Not a great sign.

Does the "caching containers for Codex Cloud" mean I have some chance of being able to reuse build artifacts between tasks? My Rust project takes around 20 minutes to set up from scratch in a new Codex environment, which seems extremely expensive.

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.

They've said it's coming:

>For developers using Codex CLI via API key, we plan to make GPT‑5-Codex available in the API soon.

I saw that, but soon doesn’t inspire confidence, and is easy to overlook if they don’t. They didn’t with the previous Codex model.

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.

Wait. There's Codex support in the mobile app? But on iOS only?

Ffs...

Yeah, it's a pitty but platform support differences between iOS and Android are still alive and well. Funnily enough, the 15 has been my first iPhone ever, mainly because Android device hardware has less and less differentiators (no jack, no expandable storage, no true camera hardware innovations as seen in the Huawei pre ban, ...). iOS is far from perfect, have experienced some insane bugs despite Apple fanatics being adamant that there are none, but considering Google is now killing side loading, I see no reason to switch. A few small experimental manufacturers (Ikko, ...) not withstanding, hardware is closer to Apples product line than ever and software now offers neither flexibility, nor added stability, so what's the point, especially as even Google makes more from iOS [0], so why keep setting money on fire running that platform...

Regardless of that, Codex needs to both come to Android for parity and the app features need to be expanded towards parity with the web page.

[0] https://searchengineland.com/report-75-percent-of-googles-mo...

First time I was able to install Codex with no NPM errors. Gonna give it a shot, seems a lot slower than Claude Code but I'm only using basic Pro with ChatGPT vs. Max 100.

Do they have a GitHub action to run in GitHub, similar to Claude?

Yes https://developers.openai.com/codex/cloud/code-review

It isn't quite the same. The Claude Code action can be easily integrated into a workflow to fire automatically (like when a PR is opened).

The Codex support at the moment requires adding a comment "@codex review" which then initiates a cloud based review.

You can, however, directly invoke Codex CLI from a GitHub workflow to do things like perform a code review.

is this model just super slow to anyone else?

Extremely slow for me - takes minutes to get anything done. Regular GPT5 was much faster. Hoping it’s mostly due to the launch day.

I've been using gpt-5 on effort=high but for gpt-5-codex, try: `-c model_reasoning_effort=medium`.

On high it is totally unusable.

even on medium ... gpt-5 was way faster, at least that's my first impression

I have seen fluctuations in token/sec. Early yesterday, roughly equivalent to none Codex GPT-5 (this branding ...), late yesterday I had a severe drop off in token/sec. Today, it seems to have improved again and with the lowered amount of unnecessary/rambling token output, GPT-5-Codex (Medium) seems faster overall. LLM rollouts always have this back and forth in token/sec, especially in the first few days.

OpenAI is starting its new era of specialized models. Guess they gave up on a monolithic model approach

If you try to optimize for everything you get a model that's good at nothing (or hyper expensive to train and run). Simple economics. There is no free lunch.

Has anyone hit any programming usage limits with the ChatGPT 5 Pro account?

None yet, feels unlimited. Huge repos too

Still waiting on codex cli to support lm studio.

? 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.

I never managed to get it to work. I used chatgpt to try to do it for me :)

This is how I did it - https://github.com/openai/codex/blob/main/docs/config.md#mod...

I have it go to openrouter, and then you just export the API key and run codex, works smoothly.

Do they demand biometrics to use it?

Agent-1

Take off the guardrails and let humanity thrive.

It is inevitable.

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