[hansonw]

Rest assured that we are better at training models than naming them ;D

- New benchmark SOTAs with 77.9% on SWE-Bench-Verified, 79.9% on SWE-Lancer, and 58.1% on TerminalBench 2.0

- Natively trained to work across many hours across multiple context windows via compaction

- 30% more token-efficient at the same reasoning level across many tasks

Let us know what you think!

[sinatra]

I currently use GPT‑5.1-Codex High and have a workflow that works well with the 5-hour/weekly limits, credits, et al. If I use GPT‑5.1-Codex-Max Medium or GPT‑5.1-Codex-Max High, how will that compare cost / credits / limits wise to GPT‑5.1-Codex High? I don't think that's clear. "Reduced tokens" makes me think it'll be priced similarly / lower. But, "Max" makes me think it'll be priced higher.

[qsort]

Codex is an outstanding product and incremental upgrades are always welcome. I'll make sure to give it a try in the coming days. Great work! :)

[agentifysh]

did you address this https://github.com/openai/codex/issues/6426 ?

how much more token efficient is this compared to 5.0

had to use 5.0 because 5.1 was eating tokens like crazy and seemed like a slight incremental improvement barely noticeable

[carbocation]

It would be great to have access to this model via the chat interface, even if it was gated behind the "other models" dropdown or something.

[iyn]

Looks like a great change! I'll take it for a spin in a moment.

I really like the "subagent" feature in Claude Code — it's super useful to manage context in complex codebases. Here are some examples of agents that can be useful: https://github.com/humanlayer/humanlayer/tree/main/.claude/a...

Would it make sense to have a similar feature in Codex CLI? I often do "spec-driven development", which is basically a loop of:

    research -> implementation plan -> actual implementation (based on research + plan) -> validation

I have multiple subagents that I use for each phase that (based on subjective judgement) improve the output quality (vs keeping everything, every tool use etc. in the "main" context window).

Codex CLI is great and I use it often but I'd like to have more of these convenient features for managing context from CC. I'm super happy that compaction is now available, hopefully we'll get more features for managing context.

[killcoder]

It would be nice if users of the codex-cli that are just using API keys as a way to handle rate limits and billing could receive these new models at the same time. I appreciate the reasoning behind delayed 'actual API' release, but I've found the rate limiting to be quite annoying, and my own API keys don't have this limitation.

[ineedasername]

Re: rate limits, I'm not sure they can, yet, on capacity. See Jensen's comment today about their cloud GPUs being sold out. So capacity increased await the ongoing data center build out.

[killcoder]

> 30% more token-efficient at the same reasoning level across many tasks

But they're claiming it's more token efficient, so me switching my usage to the new model should _free up_ capacity.

[NitpickLawyer]

Will -minis come for the codex family of models? About two months ago I used 5-mini as a daily driver for a few weeks and quite liked it, it seemed capable enough on small tasks with some hand holding and the speed/price were great as well.

[coder543]

codex-mini was released a couple of weeks ago: https://platform.openai.com/docs/models/gpt-5.1-codex-mini

[NitpickLawyer]

Thanks! I somehow missed that. Will check it out.

[robotswantdata]

Sorry don’t like the max model, feels like it needs a lot more guiding. The plans it writes however are better, so I tried feeding it back in (meta prompt style) and working okay so far. Very large repository.

[baby]

Did you guys fix not being able to enable websearches or configure no timeouts for specific commands in the SDk (error 124 is way too common for long running tasks)

[andai]

So context window is still 400k but the model got good at removing irrelevant context?

[baby]

Or is more succinct in its thoughts

[SoKamil]

> Natively trained

What does it even mean?

[kaveh_h]

Probably that before it was given system instructions on how to do compaction and now the compaction is learned by the model making it a native ability of the model without any extra instruction used in the prompt.

[ineedasername]

Continuous pre training or fine tuning, instead of inference-time instructions. It's also possible synthetic data for this purpose was in the pre training as well, and they're now getting it to behave the way they'd like.

[EnPissant]

Compaction is just what Claude Code has done forever, right?

[GardenLetter27]

I think the point here is not that it does compaction (which Codex also already does) - but that the model was trained with examples of the Codex compaction, so it should perform better when compaction has taken place (a common source for drops in performance for earlier models).

[EnPissant]

Codex previously did only manual compaction, but yeah, maybe some extra training for compaction, too?

[enraged_camel]

I am also trying to understand the difference between compaction, and what IDEs like Cursor do when they "summarize" context over long-running conversations.

Is this saying that said summarization now happens at the model level? Or are there other differences?

[typpilol]

Afaik, there's no difference besides how aggressive or not it is.

But it's the same concept. Taking tokens in context and removing irreverent ones by summarizing, etc

[baby]

Codex couldnt do what claude did before when reaching full context window

[d4rkp4ttern]

My understanding is that they trained it to explicitly use a self-prune/self-edit tool that trims/summarizes portions of its message history (e.g. use tool results from file explorations, messages that are no longer relevant, etc) during the session, rather than "panic-compact" at the end. In any case, it would be good if it does something like this.

[baby]

Yes. It was missing in codex until now