Discussion summary
GPT-5.6 Sol Ultra is a new model announced by OpenAI, part of the Codex series, with mixed reactions to its naming conventions.
What the discussion says
- Some users criticize the naming scheme as confusing or meaningless.
- Others see the release as a potential gamechanger for AI coding tools.
- There is a general interest in how these models compare to competitors like Anthropic.
“And this is a level beyond Sol, I call it Super Sol 2.”
“It's a proper noun: the name given to their latest and greatest model.”
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- Hacker News
- The full conversation https://xcancel.com/haider1/status/2073695124220006575#mby asn0
- Here's the correct link, not sure what happened with that first one https://xcancel.com/thsottiaux/status/2073933490513752151by asn0
- This is such a sad state of the industry that a reply to a tweet is now considered like an announcement by the company.
No context, nothing, just a title and a random link to a tweet, which has a seemingly relevant response from someone who works at OpenAI I guess.
by elAhmo - Will it have similar limited access like Fable? It is an interesting timeline, as general access for Fable (without using extra credits) is coming to an end :(by xcjsam
- It is like with drug dealers, you get some free dose, then cheap one, then you pay an arm and a leg.
Somebody has to finaly pay for these heaps of accelerator hardware.
by imhoguy - Related:
Previewing GPT‑5.6 Sol: a next-generation model
- Has anyone already tried 5.6 Sol in their day to day coding/development activities?
How does it compare to GPT-5.5?
by throwaw12 - Has it been released yet? I'm not seeing GPT 5.6 anywhere in the selectors, nor any announcement about it, but you're talking about it as it's already been released?
- I still don't know why OpenAI doesn't put gpt-5.5-pro in Codex. It's one hell of a model and easily parallels Fable/Mythos. Sure, it'll use up your quota much faster but that's the price some users are willing to pay for absolutely high quality responses.
I think gpt-5.5-pro runs 12x parallel gpt-5.5 agents behind the scene and uses OpenAI's secret sauce to synthesize their answers into one insanely good response.
by behnamoh - Is it as good as Fable..? Fable is the first model that mostly writes without the AI slop format for me, and so I can comfortably actually copy and paste most of what it spits out.
OpenAI models have always been the worst in my experience for verbose, slop formatted responses, with each generation increasing in sloppiness.
by aetherspawn - https://developers.openai.com/api/docs/models/gpt-5.5-pro
> GPT-5.5 Pro does not offer a cached input discount.
I think this tells you in one line. It's basically set up for one-shot inference right now, by the looks of things. If you use this in a harness, it would almost immediately fall apart on cost. Not to say that they couldn't make it work, just saying that at least as it's delivered currently, they haven't done so. On the web, there might be doing something to get the equivalent of that behavior internally, such as keeping the session truly alive on GPUs rather than using their external-facing cache-style approach.
by tekacs - I recently have been testing ChatGPT business at work and the quota seems to disappear almost instantly even using weaker models. Unless they dramatically increase their quotas it’ll be unusable.by shusaku
- many of us and myself have been using chatgpt pro from codex cli for months nowby agentifysh
- Forget 5.5-pro. Why isn't everyone talking about the fact that there's no 1M context window model in codex?
Yes, I know attention degrades above ~200k, but it's still useful in many applications.
by gck1 - API pricing ends up being something like 20x more expensive for GPT 5.5 Pro than GPT 5.5 for actual work, even though the token cost is "only" 6x. On benchmarks where I've run both, I saw $1.12 mean per task with 5.5 and nearly $23 per task with 5.5 Pro, I guess it chews longer and harder on the problem.
If that's at all reflective of what it costs them to run it, I imagine they're in the same boat as Anthropic with Fable; they probably can't afford to offer it at subscription prices given current cost to operate it.
If 5.6 Sol Ultra has efficiency improvements (at one or more layers), and it allows OpenAI to offer a model that's competitive with Fable on the subscription plans, I'll guess a lot of folks will switch.
Fable is notably better than what came before. I watched it figure out stuff on its own over and over, on extremely hard problems, that I previously needed to guide a model to an understanding about, or work with them back and forth for several turns to figure it out together. Like, I've been reverse engineering a hardware device lately, and I've tried to tackle it a few times in the past with both some version of GPT and a couple of versions of Opus (most recently 4.7). In all cases, I barely made progress...would have gotten there eventually, probably, as I'm stubborn, but there were roadblocks constantly, with me and the models getting stumped and going around in circles in the end on every prior attempts.
Fable figured out other ways to find out what's happening, it dug into config files, found and extracted Boost-serialized data, compared that data to the observed behavior, built tools to compare the observed data with our emulated behavior, without being prompted. Would I have gotten there? Eventually, maybe. All prior models didn't; they mostly just tried the things I suggested and stopped at "well, that didn't work" or declared success after seeing results that matched their misunderstanding of the problem. I guess it's possible my prior attempts with other models had "loosened the lid" on the problem; we did already have a long list of documented "this didn't work" and a pile of tools for finding out if something worked. But, even so, I was impressed.
There probably will still be a "OK, let's rewrite this so it's not using lookup tables to precisely simulate the hardware behavior in software, because we don't need the noise, too" stage of the process...but, in one day with Fable, it solved a problem that I'd banged on for at least a week or too in the past with very little real progress. I don't think the models write exceedingly good code, even the best ones, but it sure does figure shit out quick.
by SwellJoe - Recently, I've been so eager to get new model releases in Codex. I'm hooked. I hope this accelerates development. Shows how dependant I have become to Codex.
- Hope this forces Anthropic to be less stingy with Fable.by internet2000
- It is not because they want to but because they literally don't have the capacity to.by satvikpendem
- Hopefully they aren't, and their business dies. They're not a good company.by nullbio
- Yeah. I'll switch to OpenAI if they release Sol on their subscription tiers.
- Not including their best model in a max subscription would otherwise be truly a good reason for once to consider going back to openai for me. I'll at least try it.by jascha_eng
- For context:
> Additionally, we’re introducing a new ultra mode that goes beyond the capabilities of a single agent by leveraging subagents to accelerate complex work.
https://openai.com/index/previewing-gpt-5-6-sol/
Can someone explain how this compares with Pro? I thought Pro was already something similar.
by andai - i would believe this will be matched with something like orchestrator-focused model: https://news.ycombinator.com/item?id=48624782by ilsubyeega
- Pro also makes you ask it to use sub-agents instead of just doing it when useful.
Hopefully, 5.6 will automatically spawn sub-agents without needing to ask.
by patentlyze - How is this any different than what we have already? We've had this ability for ages (6+ months, decades in the AI world), you can literally today easily prompt CC or Codex to use subagents to accomplish tasks and they'll do it well. My entire workflow is one top level orchestrator chat creating tickets to dispatch to subagents to implement, and other subagents to verify. Why is this being sold as a new thing? Have HN users never tried tried asking CC or Codex to use subagents?by gbnwl
- I imagine this is something like Anthropic's dynamic workflows where a JS file is created to make a little AI harness on the spotby ludamad
- For pro mode the agents worked independently and only when they all finished did a new agent take a look at everything to merge the work into a single response. The new thing involves subagents that have been trained to cooperatively pursue a task and are allowed to communicate with each other along the way.
- I wonder if it's related that that OpenAI has found a way to cut inference costs by half, according to The Information.
https://www.theinformation.com/newsletters/ai-agenda/openai-...
by postalcoder - What’s the technique? And did they buy it from thinking machines?
- Semi-related, has anyone noticed their GPT 5.5 usage in Codex being cut in half as of a couple days ago? I got a lot more mileage out of my session usage yesterday for the same workload.by minimaxir