[granzymes]

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.

[the_duke]

I do not trust the AI benchmarks much, they often do not line up with my experience.

That said ... I do think Codex 5.2 was the best coding model for more complex tasks, albeit quite slow.

So very much looking forward to trying out 5.3.

[NitpickLawyer]

Just some anecdata++ here but I found 5.2 to be really good at code review. So I can have something crunched by cheaper models, reviewed async by codex and then re-prompt with the findings from the review. It finds good things, doesn't flag nits (if prompted not to) and the overall flow is worth it for me. Speed loss doesn't impact this flow that much.

[aurareturn]

5.2 Codex became my default coding model. It “feels” smarter than Opus 4.5.

I use 5.2 Codex for the entire task, then ask Opus 4.5 at the end to double check the work. It's nice to have another frontier model's opinion and ask it to spot any potential issues.

Looking forward to trying 5.3.

[fooker]

Yeah, these benchmarks are bogus.

Every new model overfits to the latest overhyped benchmark.

Someone should take this to a logical extreme and train a tiny model that scores better on a specific benchmark.

[mmaunder]

ARG-AGI-2 leaderboard has a strong correlation with my Rust/CUDA coding experience with the models.

[int_19h]

Codex 5.3 seems to be a lot chattier. As in, it comments in the chat about things it has done or is about to do. They don't show up as "thinking" CoT blocks, but as regular outputs, but overall the experience is somewhat more like Claude is in that you can spot the problems in model's reasoning much earlier if you keep an eye on it as it works, and steer it away.

[jahsome]

Another day, another hn thread of "this model changes everything" followed immediately by a reply stating "actually I have the literal opposite experience and find competitor's model is the best" repeated until it's time to start the next day's thread.

[nerdsniper]

Opus 4.5 still worked better for most of my work, which is generally "weird stuff". A lot of my programming involves concepts that are a bit brain-melting for LLMs, because multiple "99% of the time, assumption X is correct" are reversed for my project. I think Opus does better at not falling into those traps. Excited to try out 5.3

[leumon]

they tested it at xhigh reasoning though, which is probably double the cost of Anthropic's model.

Cost to Run Artificial Analysis Intelligence Index:

GPT-5.2 Codex (xhigh): $3244

Claude Opus 4.5-reasoning: $1485

(and probably similar values for the newer models?)

[redox99]

With $20 gpt plan you can use xhigh no problem. With $20 Claude plan you reach the 5h limit with a single feature.

[Computer0]

A provider's API costs seemingly do not reflect each respective SOTA provider's subscription usage allowances.

[wilg]

In my personal experience the GPT models have always been significantly better than the Claude models for agentic coding, I’m baffled why people think Claude has the edge on programming.

[dudeinhawaii]

I think for many/most programmers = 'speed + output' and webdev == "great coding".

Not throwing shade anyone's way. I actually do prefer Claude for webdev (even if it does cringe things like generate custom CSS on every page) -- because I hate webdev and Claude designs are always better looking.

But the meat of my code is backend and "hard" and for that Codex is always better, not even a competition. In that domain, I want accuracy and not speed.

Solution, use both as needed!

[soulofmischief]

GPT 5.2 codex plans well but fucks off a lot, goes in circles (more than opus 4.5) and really just lacks the breadth of integrated knowledge that makes opus feel so powerful.

Opus is the first model I can trust to just do things, and do them right, at least small things. For larger/more complex things I have to keep either model on extremely short leashes. But the difference is enough that I canceled my GPT Pro sub so I could switch to Claude. Maybe 5.3 will change things, but I also cannot continue to ethically support Sam Altman's business.

[fragmede]

How many people are building the same thing multiple times to compare model performance? I'm much more interested in getting the thing I'm building getting built, than than comparing AIs to each other.

[__jl__]

Impressive jump for GPT-5.3-codex and crazy to see two top coding models come out on the same day...

[granzymes]

Insane! I think this has to be the shortest-lived SOTA for any model so far. Competition is amazing.

[nurettin]

Opus was quite useless today. Created lots of globals, statics, forward declarations, hidden implementations in cpp files with no testable interface, erasing types, casting void pointers, I had to fix quite a lot and decouple the entangled mess.

Hopefully performance will pick up after the rollout.

[nickstinemates]

Did you give it any architecture guidance? An architecture skill that it can load to make sure it lays out things according to your taste?

[jronak]

Did you look at the ARC AGI 2? Codex might be overfit for terminal bench

[tedsanders]

ARC AGI 2 has a training set that model providers can choose to train on, so really wouldn't recommend using it as a general measure of coding ability.