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GPT-5.6

1504 pointsby logickkk1yesterday at 5:04 PM1066 commentsview on HN

https://deploymentsafety.openai.com/gpt-5-6/gpt-5-6.pdf

https://developers.openai.com/api/docs/guides/latest-model

https://x.com/levie/status/2075287443411222628, https://xcancel.com/levie/status/2075287443411222628


Comments

cmrdporcupinetoday at 3:24 PM

After some time with it...

It has a tendency to do things without asking, a trait I'd associated more with the Claude Opus & Sonnet models than with Codex & GPT in the past. Specifically I've seen it go and update e.g. README.md files filling it with recenty-biased gibberish that means nothing to the user (e.g. very specific technical notes related to what it was currently working on) or staging and adding design/spec documents that were meant to just be working documents. In general it tends to behave more aggressively with git, if you let it get its hands on it. It has stronger "opinions" on that stuff, that don't always agree with me.

I'm going to have to update my prompts, I think. But I'm not used to this kind of thing in Codex, which in the past has been much more explicit and cautious, and one of the reasons I've preferred it over Claude.

It is very "smart." It also has a tendency to yak-shave things. Producing huge volumes of correctness and regression tests and nitting over e.g. very minor variances.

One thing that is "entertaining" is letting two separate instances review each other's code. They will endlessly find things to nit at.

nharziroyesterday at 5:17 PM

where is it? Still not accessible...

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_bobmtoday at 8:25 AM

are people getting the `<!-- -->` sentinel'd reasoning summaries?

raketenkateryesterday at 10:08 PM

5.6 sol ultra just nuked my branch and burned my 5h limit. nice work

kubbyesterday at 5:16 PM

They have a fantastic media team.

breatheoftenyesterday at 7:24 PM

i wish they had renamed chatgpt to codex instead of the other way around ...

vatsachakyesterday at 6:03 PM

I wonder what increment of progress will be achieved by the next billion dollars

EugeneOZyesterday at 7:21 PM

GPT 5.6 Sol is a token hog. After implementing the task, it started some "reviews" I didn't ask for - they consumed 19.5M and 11.9M tokens, while the task itself was below 5M tokens.

hereme888yesterday at 5:33 PM

So is 5.5-Daybreak still relevant for cyber security give. 5.6 capabilities?

sunaookamiyesterday at 6:57 PM

Overloaded in Codex, no indication if it is already in ChatGPT and I can't use it in the API even though it says it should be available. Typical horrible OpenAI launch. Glad that Anthropic just reset the rate limits so I will go back to Fable again.

int3trapyesterday at 11:13 PM

5.6 SOL is basically useless, even on fast mode. It takes so long to do anything that it would be faster to do yourself. And it burns usage so quickly it's genuinely not worth it.

Lucasoatoyesterday at 11:02 PM

> This page couldn’t load

> Reload to try again, or go back.

This on iOS, safari

dayone1yesterday at 8:43 PM

does anyone on chatgpt business plan (not enterprise) not have access to the Sol models in codex? i have 5.6 for terra and luna but not sol

fractorialyesterday at 5:57 PM

Sounds like a perfect fit for a minimal or bespoke harness?

drsalttoday at 12:41 AM

they update these shits too much.

hyperknotyesterday at 6:02 PM

> GPT‑5.6 also introduces more predictable prompt caching, including support for explicit cache breakpoints (opens in a new window) and a 30-minute minimum cache life.

Great to read they are moving away from the 5 minute cache defaults. Hopefully other providers follow soon!

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browskiyesterday at 5:27 PM

Here's me using a Gemini chat log scraper (from Gdrive) then dumping my prompt+Gemini response into local AI

Never go over the free limits in Gemini Pro.

Gemini is great at research and architecture, and my 30 years experience in programming everything; for fun or work; means together there is little to no code slop.

Add to project repo some git submodules of reference source code; boom, bobs your uncle

Zero reason to sign up for OAI or Claude. With employers realizing the costs are more than employees, local models getting more powerful, and models in chips just a few years out, neither of the one note LLM companies without diversified services and R&D portfolios gonna last

epolanskitoday at 9:11 AM

I'm using luna (the smallest), at low thinking in my 9-to-5 job and I'm quite happy. No groundbreaking tasks so far, but typical small jira issues and fixes are done in a matter of low minutes. Very fast loops have their pros.

Fable or Opus would wander and wander.

maxdoyesterday at 5:51 PM

cursor benchmarks with GPT 5.6 in picture, a good reason to stop using opus.

https://cursor.com/evals

The good news you don't have to send your dollars to China to fund ai dictatorship, in russia, north korea, african countries and south america.

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cmrdporcupineyesterday at 7:01 PM

Almost immediately ran into some the kind of gatekeeping I've heard Claude Code users complaining about with Fable. Not sure why, I just had it working on writing benchmarks for some CUDA kernels. Nothing security related:

"This request requires additional safety checks, which can take extra time. Hang tight or retry with a faster model for a quicker response, though it may be less capable of handling complex requests."

At least it gave me the option of waiting instead of just unceremoniously downgrading me. Appears to be making progress but... weird?

ls612yesterday at 6:47 PM

I think the most interesting part of this is that OpenAI is going way easier on the classifiers than Anthropic. They explicitly state that many defensive cybersecurity uses are supported and implicitly criticize Anthropic's stance on Fable's uses by saying that overblocking cyber requests is itself a major security risk as more AI models continue to advance in intelligence. I have so many questions as to what is going on on a game theoretic level in the AI space in the past two months, it seems like multiple actors have realized their incentives are really quite different than they originally thought.

paul7986yesterday at 6:36 PM

For writing GPT which i was subscribed to Fall 2024 to March 2026 (laid off) is superior to Gemini. Been using Gemini since March mostly and they offered a $10 a month plan so i took it. Though today realizing GPT is superior to help me write I am back to being a paying customer. Im in full swing mode to get back into the job market (get the heck away from UI/UX which is now a stupid career in terms of number of jobs out there and in the future there will continue to be less) pivoting into product management (can vibe code anything now) and or customer relations. Hopefully GPT helps me with this pivot and Im again gainfully employed!

newfriendyesterday at 5:14 PM

>Even at medium reasoning, it beats Fable 5 by 11.4 points at roughly one-quarter the estimated cost.

Sounds great.

Also latency looks very good.

saberienceyesterday at 5:10 PM

"On Agents’ Last Exam (opens in a new window), an evaluation of long-running professional workflows across 55 fields, GPT‑5.6 Sol sets a new high of 53.6, eclipsing Claude Fable 5 (adaptive reasoning) by 13.1 points. Even at medium reasoning, it beats Fable 5 by 11.4 points at roughly one-quarter the estimated cost. That efficiency extends to smaller models, which are essential to making intelligence more abundant and affordable: GPT‑5.6 Terra and GPT‑5.6 Luna outperform Fable 5 at around one-sixteenth the cost. "

Some pretty big claims and results! Excited to see how it feels during usage.

I use Fable and 5.5 extensively and I still find both have a place in my toolkit, i.e. Fable IS good but it isn't perfect, and it's still better to play them off against each other. I have Fable and 5.5 write plans and have them adversarially review each other's plans.

Having this amount of competition in the coding model space is good for all of us.

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guybedoyesterday at 7:04 PM

It's good to see labs taking into account the cost/task.

Grok 4.5 is interesting because it's smart enough at great price. It seems gpt 5.6 is right there with great efficiency and great pricing.

Working with Fable has been a great experience, but at the end of the day, if you can get only 10% of your work done because it just burns through tokens, that's not that interesting.

I've been mostly using Opus and Fable high for planning and codex 5.5 medium for implementations. Claude is also the only model i can use for design tasks. If gpt 5.6 can finally deliver on the design side, it might be time to ditch the Claude sub and go full Gpt.

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imilevtoday at 10:24 AM

Cannot believe I needed a VPN to the US, to open this from Switzerland...

At least give me the article ffs.

yayamaoyesterday at 10:11 PM

good alternative, while gemini still no news

mydreamofyesterday at 7:27 PM

Bro these colors on chars are unbelievlable, I can not understand which is opus, which is fable, which is GPT...

bearmaniayesterday at 5:38 PM

If OpenAI can add all the features from CC into Codex i’ll gladly switch.

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RagnarDyesterday at 11:23 PM

Annoyingly, the new ChatGPT app which folds in Codex, no longer recognizes Shift-Tab to toggle plan mode. Irritatingly you have to enter /plan. OpenAI, fix this!

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simianwordsyesterday at 8:26 PM

GPT Terra is 50% cheaper than 5.5 while being more performant. So it’s like a straight up 50% reduction in cost!

That leads me to a question. Why wouldn’t they just default to terra in ChatGPT in the last few months? If they didn’t then they burnt money for no reason by giving a shittier model at a higher price

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gverrillayesterday at 7:59 PM

If Fable is removed from my Anthropic sub, I'll have to change to OpenAI.

golangdevyesterday at 6:32 PM

good alternative to anthropic

brcmthrowawayyesterday at 7:02 PM

Benchmaxxed

OutOfHereyesterday at 6:04 PM

Like the last time, again they failed to note whether there is an Instant model or when it might become available.

Razenganyesterday at 6:02 PM

Just a day before my $100 subscription expires, perfect

diwankyesterday at 6:24 PM

i'm not happy with how openai is trying to pit 5.6 sol as a cheaper equivalent to fable here

for one thing, they said that on AA, sol is "within one point of fable" at 58.9 vs 59.9 but don't clarify that the latter is with safeguards where ~8% of the tasks got routed to opus

i'm not rooting for either and genuinely think that the token efficiency and cheaper price are important but this sort of thing just feels disingenuous :-/

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therobots927yesterday at 5:13 PM

Do they expect us this model is 15ppt more accurate at half the price of fable? What’s going on?

dude250711yesterday at 5:13 PM

Not available - checked and it's not there.

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bearmaniayesterday at 5:40 PM

if OpenAI adds all the features from CC into Codex, i’ll gladly switch.

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tipiiraiyesterday at 5:10 PM

Thought Fable was great

gozucitoyesterday at 5:16 PM

The meat of the report for SWEs:

SWE-Bench Pro Sol: 64.6% Fable: 80% Opus: 69.2% (!!!!)

So, it still trails Opus, significantly, and is not a next-gen coding model like Mythos/Fable 5.

Disappointing to say the least, but somewhat expected.

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ddxvyesterday at 5:46 PM

I'm disappointed these models continue to be closed source and so expensive.

Open weight models being 10x or more cheaper is just so much more of an unlock than incremental gains for me.

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simianwordsyesterday at 5:24 PM

> On the Artificial Analysis Coding Agent Index, GPT‑5.6 Sol with max reasoning sets a new state of the art at 80, 2.8 points above Fable 5, while using less than half the output tokens, taking less than half the time, and costing about one-third less.

> That advantage extends across the family: Terra performs just above Fable 5, while Luna outperforms Opus 4.8; each does so in roughly one-third of the time, with about half as many output tokens, and at approximately one-quarter the estimated cost.

Wow. I don't believe it. Every indication and twitter post told me that Fable is much more intelligent than Sol and here we are told that even Terra outperforms Fable?

Not only that, Sol doesn't even come with run time classifiers. So it is even more suspicious.

What's even stranger is that OpenAI is directly referencing a competitor in this direct way.

rvzyesterday at 5:10 PM

Most importantly, the cost:

> GPT‑5.6 is priced per 1M tokens across three model sizes: Sol is $5 input / $30 output; Terra is $2.50 input / $15 output; and Luna is $1 input / $6 output.

Just as expensive as Fable 5. But of course, another slot machine upgrade but the costs will keep going up and the open weight models from china will continue to race everyone else to $0.

Looking forward to the next version of GLM, Qwen, Deepseek and Minimax.

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stanmayyesterday at 11:05 PM

sol is good

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