6 ms·

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 see

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_5_codex_prompt.md https://github.com/openai/codex/blob/main/codex-rs/core/gpt_... [1]https://github.com/openai/codex/blob/main/codex-rs/core/prompt.md https://github.com/openai/codex/blob/main/codex-rs/core/prom...

pants2 1y ago
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 1y ago
  think they're indexing here for professional work (people in the VSCode terminal)
- jumploops 1y ago
  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.
  - Turskarama 1y ago
    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.
    - animegolem 1y ago
      I've found if you prompt a persona with these expectations GPT is pretty good at honoring it.
tedsanders 1y ago
> 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 https://x.com/brhydon/status/1953648884309536958
- dwaltrip 1y ago
  so annoying you cant read replies without an account nowadays
  - Tiberium 1y ago
    Use Nitter, the main instance works but there are a lot of other instances as well. https://nitter.net/brhydon/status/1953648884309536958 https://nitter.net/brhydon/status/1953648884309536958
  - dcre 1y ago
    Change the url from x.com to xcancel.com to see it all.
siva7 1y ago
So you're all saying suddenly codex cli w gpt 5 codex is better than claude code? Hard to believe
- jumploops 1y ago
  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.
  - srcreigh 1y ago
    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.
    - elcritch 1y ago
      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.
  - j45 1y ago
    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.
groby_b 1y ago
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)
- artemisart 1y ago
  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.
  - jumploops 1y ago
    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.
  - groby_b 1y ago
    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)
j45 1y ago
I wonder if this means part of the prompt has been moved to a higher level somehow... or baked into the bread elsewhere.

pants2 1y ago

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 1y ago
think they're indexing here for professional work (people in the VSCode terminal)
jumploops 1y ago
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.
- Turskarama 1y ago
  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.
  - animegolem 1y ago
    I've found if you prompt a persona with these expectations GPT is pretty good at honoring it.

tedsanders 1y ago

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

dwaltrip 1y ago
so annoying you cant read replies without an account nowadays
- Tiberium 1y ago
  Use Nitter, the main instance works but there are a lot of other instances as well. https://nitter.net/brhydon/status/1953648884309536958 https://nitter.net/brhydon/status/1953648884309536958
- dcre 1y ago
  Change the url from x.com to xcancel.com to see it all.

siva7 1y ago

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

jumploops 1y ago
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.
- srcreigh 1y ago
  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.
  - elcritch 1y ago
    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.
- j45 1y ago
  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.

groby_b 1y ago

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)

artemisart 1y ago
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.
- jumploops 1y ago
  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.
- groby_b 1y ago
  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)

j45 1y ago

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