alt Hacker NewsWeirdly, the blog announcement completely omits the actual new context window size which is 400,000: https://platform.openai.com/docs/models/gpt-5.2
Can I just say !!!!!!!! Hell yeah! Blog post indicates it's also much better at using the full context.
Congrats OpenAI team. Huge day for you folks!!
Started on Claude Code and like many of you, had that omg CC moment we all had. Then got greedy.
Switched over to Codex when 5.1 came out. WOW. Really nice acceleration in my Rust/CUDA project which is a gnarly one.
Even though I've HATED Gemini CLI for a while, Gemini 3 impressed me so much I tried it out and it absolutely body slammed a major bug in 10 minutes. Started using it to consult on commits. Was so impressed it became my daily driver. Huge mistake. I almost lost my mind after a week of this fighting it. Isane bias towards action. Ignoring user instructions. Garbage characters in output. Absolutely no observability in its thought process. And on and on.
Switched back to Codex just in time for 5.1 codex max xhigh which I've been using for a week, and it was like a breath of fresh air. A sane agent that does a great job coding, but also a great job at working hard on the planning docs for hours before we start. Listens to user feedback. Observability on chain of thought. Moves reasonably quickly. And also makes it easy to pay them more when I need more capacity.
And then today GPT-5.2 with an xhigh mode. I feel like xmass has come early. Right as I'm doing a huge Rust/CUDA/Math-heavy refactor. THANK YOU!!
Replies
> Weirdly, the blog announcement completely omits the actual new context window size which is 400,000: https://platform.openai.com/docs/models/gpt-5.2
As @lopuhin points out, they already claimed that context window for previous iterations of GPT-5.
The funny thing is though, I'm on the business plan, and none of their models, not GPT-5, GPT-5.1, GPT-5.2, GPT-5.2 Extended Thinking, GPT-5.2 Pro, etc., can really handle inputs beyond ~50k tokens.
I know because, when working with a really long Python file (>5k LoCs), it often claims there is a bug because, somewhere close to the end of the file, it cuts off and reads as '...'.
Gemini 3 Pro, by contrast, can genuinely handle long contexts.
Context window size of 400k is not new, gpt-5, 5.1, 5-mini, etc. have the same. But they do claim they improved long context performance which if true would be great.
have been on 1M context window with claude since 4.0 - it gets pretty expensive when you run 1M context on a long running project (mostly using it in cline for coding). I think they've realized more context length = more $ when dealing with most agentic coding workflows on api.
I haven't done a ton of testing due to cost, but so far I've actually gotten worse results with xhigh than high with gpt-5.1-codex-max. Made me wonder if it was somehow a PEBKAC error. Have you done much comparison between high and xhigh?
>Can I just say !!!!!!!! Hell yeah!
...
>THANK YOU!!
Man you're way too excited.
Usable input limit has not changed, and remains 400 - 128 = 272. Confirmed by looking for any changes in codex cli source, nope.
Anecdotally, I will say that for my toughest jobs GPT-5+ High in `codex` has been the best tool I've used - CUDA->HIP porting, finding bugs in torch, websockets, etc, it's able to test, reason deeply and find bugs. It can't make UI code for it's life however.
Sonnet/Opus 4.5 is faster, generally feels like a better coder, and make much prettier TUI/FEs, but in my experience, for anything tough any time it tells you it understands now, it really doesn't...
Gemini 3 Pro is unusable - I've found the same thing, opinionated in the worst way, unreliable, doesn't respect my AGENTS.md and for my real world problems, I don't think it's actually solved anything that I can't get through w/ GPT (although I'll say that I wasn't impressed w/ Max, hopefully 5.2 xhigh improves things). I've heard it can do some magic from colleagues working on FE, but I'll just have to take their word for it.