Improving GPT‑5.6 Sol in ChatGPT, expanding GPT‑5.6 Luna access for free users
openai.comGiving free ChatGPT users access to reasoning (the 'Think' toggle) will have a broader impact on the world than every new paid model and coding agent combined.
Going from 5.5 Instant (which was noticeably bad) to 5.6 Luna is a big jump as well. OpenAI is probably the most prominent among the general public - an advantage in some respects but they're giving away a lot of free inference and thus have to use a pretty small model to do it.
I really don't see how they're going to be google here. The free tier is dominated by verticle integration and the platform that people use. Long term I imagine google wins the bottom of the market and I'd be suprised if they lost.
Even a long while ago it was estimated that every Google search cost google several cents (and that they made back 10 cents). Google also uses AI for search results. Thus its not inconceivable that openai can make money here.
Ads.
Ads work when you can server $.01 worth of ads to a user for $.0001 of server cost. I fail to see how you can make it work when doing LLM inference which is significantly costlier than web search.
In about 4 months, OpenAI’s fundraiser decks will leak, which will include their current ad revenue.
I recently saw some discussion about the CPC for personal injury lawyers being ~$200 on Google ads. Seems insane to me, but I’m totally disconnected from the advertising world. That said, depending on the conversion rates between chats and clicks, the math could be favorable for OAI.
High CACs are supported by high LTVs, that is about the right ballpark for things like lawyers or even plumbers.
> I fail to see how you can make it work when doing LLM inference which is significantly costlier than web search.
The median LLM query isn't significantly costlier than web search.
90+% of queries are probably so common/evergreen that, if a cheaper model made all the different language varients and ways of asking the question into one query, they could be cached quite effectively.
Except that Google is giving AI answers for ~every search now, so they're paying that cost for every search now as well.
People tell these models everything. You don't think a pretty unethical company can figure out a way to monetize that?
Does the free tier really not have access to reasoning models?
That would explain a lot of the terrible AI/LLM takes online.
The free tier of ChatGPT is powered by GPT-5.5 Instant, a non-reasoning version of GPT 5.5.
I'm not sure people fully comprehend the trickle-down pop-culture/zeitgeist effects that LLM's are having/are going to have on humanity.
Because everyone now outsources much of their thinking and researching to LLM's, our collective culture + brain is shaped in a cyclical manner by using them.
It's the mechanical homogenization of culture and groupthink.
Free users have had access to reasoning for a while. o4-mini and the initial GPT-5 launch both included reasoning modes for free users.
They took away the button a few months ago and are now putting it back.
Technically yes, but the free usage equated to single-digit messages per day before the auto-downgrade. With GPT-5 it was just 1 message per day.
Perhaps I should have said "proper access".
I think it’s a misread to think the default ChatGPT model switching to GPT 5.6 Luna is some sort of desperation move. Keep in mind that Claude .ai never had this extreme stratification between the frontier models and the free tier (Sonnet is available to free users with rate limits).
So 5.6 Luna is just their next version of what they used to call 5.5 instant tier
And 5.x instant models were never much to write home about anyway so the default ChatGPT free model hasn’t been particularly distinctive since 4o
> Our mission is to ensure that artificial general intelligence benefits all of humanity. We’re introducing updates to ChatGPT that improve everyday conversations while expanding access for Free users.
This clearly implies that they believe ChatGPT models are AGI and are now willing to say it out loud.
Which I think is a fair interpretation of the term. They are general purpose intelligence in that you can get help from them about almost anything. They are not like narrow single purpose AI models.
I don't think we need that term to mean "can completely emulate a human" or "can do every task any human on earth can do as well as them".
It also needs to be differentiated from ASI with godlike powers many times greater than human.
If we could show the current models to someone like Alan Turing, I am sure he would conclude that we have AGI.
And after half an hour using it he'd just admit that his test was way too simple as these models are still way too dumb
I think of the Turing test as one of the starting lines, along with image recognition ("a summer break project for a group of grad students" resisted being solved for decades).
It is a huge leap. Now we can start talking about "intelligence" at all - we really couldn't before. That we're still hovering barely above the starting line is a separate matter (also worth noting, of course).
How are the models too dumb? How are they dumber than the average person? I wonder if anyone gave Claude an IQ test (the one for humans).
Yes there are a few sites with IQ test benchmarks. The frontier models come up around 130 or 140 depending on which model/test.
> This clearly implies that they believe ChatGPT models are AGI and are now willing to say it out loud.
Well, the models are smart enough to point out why this is wrong.
>It also needs to be differentiated from ASI with godlike powers many times greater than human.
Wasn't there a thread the other day about how very few humans on earth can understand the new math proofs?
Although "with sufficient study" vs "not even with unlimited study" are probably worth distinguishing there.
Which brings up another point in that we should have a term that distinguished between super intelligence in some capacity and godlike super intelligence.
"This clearly implies that they believe ChatGPT models are AGI and are now willing to say it out loud."
I cannot believe the comments I read on HN nowadays. ZERO critical thinking.
Well your comment adds no value and is just offensive. Why don’t you argue a counterpoint?
I can't wait to never see a reasoning button ever again. Why do I have to reason about what reasoning level to use?
I have the opposite problem. I'm not well-calibrated on when I'd want lower reasoning than what's available to me (and how to compare that to lower-tier models). OpenAI now has Luna, Terra and Sol, each at Low, Medium, High and Xhigh, with Pro/Ultra depending on harness and plan. That's ~15 possible combinations of model and reasoning level, and there isn't a satisfactory explanation of which one you want for any particular task.
I feel that work is basically split into two tiers, hard (which requires a good model and lots of reasoning by definition) and relatively easy (which won't consume much of my limits despite a great model and reasoning, so I may just as well keep it on Sol High).
Yeah, it's hard, there's so many permutations. But most are bad so it narrows it down.
Luna: Can be useful if price sensitive, always use with AT LEAST high effort. But codex plans are very generous, so just ignore it.
Terra: Forget it exists
Sol: Just use this. Medium can work for specific edits. Otherwise just use high or xhigh.
OpenAI basically agrees with this, and the slider gives you those options.
TL;DR: Just use sol medium/high/xhigh
Why not pro/ultra?
Pro: It's web chat only, I haven't tried it so idk. I think it's useful for Math and that kind of stuff, but I only do programming.
Ultra: Might be useful, the one time I tried it, it was extremely wasteful in terms of tokens. Definitely not a daily driver.
There's also max effort, I think it can be useful but the gains compared to xhigh are quite small.
I think max and ultra are only worth it when the others fail.
It’s very confusing to me. I’ve occasionally used pro to do high-level research and design. Then I ask it to create a prompt for Codex ultra. Ultra can do a lot of genetic benchmarking and testing to elucidate and resolve quandaries.
I don’t know if this is a good workflow.
Auto-effort and similarly auto model routing suffer from a halting problem sort of issue: you don’t reliably know if a request is complex unless you use a complex model to make the decision.
Some people want quick results. Some people want it to keep searching for a new math proof overnight without giving up, and they have money to burn.
It seems like giving it a time limit or a budget in dollars would be clearer, though?
Or, keep searching until I come back to the computer and ask about progress.
The _Intelligence_ part of AGI should be able to guide the user through that without all the knobs.
OpenAI tried auto-routing with the initial GPT-5 release and it was immediately clear why that was a bad idea.
intelligence is not omniscience though
Asking questions to clarify user intent is a very low bar for intelligence. A bar that all SOTA models fail consistently at though. (It's both funny and legit infuriating when Opus, after having made a dozen wild assumptions without checking with you, then comes back with a request for clarification on some mundane topic).
but you can keep asking questions ad infinitum
very nontrivial problem knowing when to stop and making assumptions
I don't understand this at all. Whenever I ask Gemini 3.1 Pro Extended, or Claude 5 Max something in chat, the most I ever wait is maybe 30 seconds. Is that really so bad?
"Wait 30 seconds" as a concept has been totally incompatible with the web, smartphones, etc for about 20 years now.
Because the model can't read your mind and know if you want a quick answer, or an hour long deep dive.
Then it should just ask the user what they want if its unclear from the context.
So instead of just getting an answer, I have to wait until it asks me, and I have to type back a response? Extremely annoying.
Exactly! I posted much the same comment in another thread and there were lots of huffy complaints that amounted to "you're prompting it wrong"
That's what the reasoning slider is for!
just wait for the loot boxes, mark my words
I absolutely need instant mode as this is what I use 90% of the time.
Sadly it's not available anymore on the updated desktop app (formerly Codex) and the previous desktop app (formerly ChatGPT) is abandoned.
Because your incentives are opposed to the provider’s incentives
I think it's nice to be able to make the model reason for dozens of minutes when you want to go deep on a topic, even if the router thinks it's an easy question.
They must really be feeling the commoditization pressure. I'm not sure what the way out of this is, ChatGPT and Claude are still good products, but they are not necessarily premium products anymore.
I expect a few things to happen in the next year:
1) Exclusive MCP server deals/API integrations
2) Significant switch to B2B marketing, even moreso than we've seen before, with API interfaces being paid and chat-client interfaces becoming more and more free, perhaps just with limits more on integrations or data visualization/analysis
3) US restrictions on B2B contracts with non-US hosted models that do any sort of contracting with the government
Obviously there's a bunch of stuff I'm not foreseeing. But it really does feel like the bottom of the market is collapsing into free. I assume OpenAI and Anthropic think their next generation of models will restore their halo tier status and that the cash burn is justified to just get there, but this has to really mess up IPO plans.
I'm not sure I agree
1) Back then, even as a free user you'd be able to use the strongest model (even if with tight limits). Now, you need to pay to use Sol, and you need to pay to use Opus or Fable. It does seem fairly premium in that sense. Idk about 5.6 Luna, but the previous Instant was really bad, even for very casual users. It would hallucinate non stop.
2) When $100 and $200 per month plans launched, they were received as outrageous even here. Nowadays they are pretty common among power users.
I also scoffed at the ChatGPT $200 Pro plan back then.
Back when coding for me still meant copy-paste from the web version, it was only worth the $20/month for me.
They only added the $100 Pro plan in April during GPT 5.4 times.
Today I happily pay $400/month for Codex and Claude Code.
Don’t say the last part out loud or it will be $800.
>1) Back then, even as a free user you'd be able to use the strongest model (even if with tight limits). Now, you need to pay to use Sol, and you need to pay to use Opus or Fable. It does seem fairly premium in that sense. Idk about 5.6 Luna, but the previous Instant was really bad, even for very casual users. It would hallucinate non stop.
This is kind of what I'm saying though. Bottom has fallen out, differentiation is just can you be much more premium than the competition. Currently that remains unanswered.
EDIT: I'm basing this off the assumption that for chat, premium is not a point of differentiation at all. For coding/analysis, it is.
especially when 99% tasks don't need fable, and certainly not the next model
Its always fun to try to read between the lines here to speculate why they are doing this.
Maybe Luna efficiency gain was actually significant enough that putting all the free users and giving them super generous limits makes sense.
They might be doing this to improve the messaging of AI among causal users since right now there is a huge amount of datacenter backlash in the US due to AI grievances.
Maybe they have too much excess capacity or they really want to juice token numbers and market share on their dashboards for marketing.
I also wonder if being given access to an actually a decent model like luna with actual thinking budget instead of brainless "instant" modes will start to make causal users understand the real capabilities of these models.
Let’s speculate: they want luna to be their first model “on silicon” and need as much test data as possible before finalizing the design.
It's also going to be more training data for them.
Is this new behavior from them? I haven't looked at their free chat offering in a minute, but I thought they always had them close behind paid tier, often with essentially equal products that made it weird for them to sell the paid tier for chat.
No, free tier was total garbage with GPT-5.
You can't even pick 5.6 luna on the chat app with a paid subscription. It just gives you sol (or use older models) with what seems like basically as much usage as you want. And sol is considerably smarter than luna.
All of this is of pretty minor importance though. You can't read as many tokens as a subcription can produce so more chat is not the value add nor super important.
I mean there are literally so many providers for free chat if you are willing to use several seperate apps.
The real value in these subs is using codex cli, much like the real point of anthropic subs is using claude code. Because agentic work actually does require a lot of tokens.
> Maybe Luna efficiency gain was actually significant enough that putting all the free users and giving them super generous limits makes sense.
Definitely this. The recent 80% discount was a reaction to Deepseek's update so that they still position near the frontier. My theory: Luna has always had a much higher efficiency. You do know that the model didn't get faster after the discount?
Nothing in the ChatGPT model release notes yet: https://help.openai.com/en/articles/9624314-model-release-no...
(This is a subtle nudge at anyone from OpenAI who reads this to make sure they get updated.)
OpenAI have a model called "chat-latest" - I wonder if that's running this new model yet: https://developers.openai.com/api/docs/models/chat-latest
It's described as "points to the latest Instant model currently used in ChatGPT" - so presumably that's "GPT-5.6 Instant" in the app.
There’s no 5.6 instant I think — 5.6 Luna is gonna be the new instant tier model
No, Luna is the new free model.
https://gist.github.com/simonw/aae4febd3c6f7bc5b7811857edb3c... has screenshots that still show "Instant" as an option for ChatGPT Chat... but not for ChatGPT Work.
Hmm
It’s hard to understand this .. like sure we can select instant but is there an actual model called 5.6 instant? Like is it on LM Arena and OpenRouter or available via API etc
5.5 instant is definitely A Thing it’s even name checked in this OAI post
It's SO hard to understand this. I couldn't confidently explain it at all.
free unlimited luna is a pretty badass move
luna is very good
Any improvement to the ChatGPT free plan is really nice. It's easy to forget that most people have never used a SOTA model, and only think of their experience with GPT-4o or Google Search's AI Overviews when asked about AI.
It's also pretty cheap if you're paying for it (for coding). But I don't quite trust it for anything complicated, so I often use Terra.
Terra is awful and not cheap enough to make up for it. I'd suggest using luna or sol.
Terra is far from awful. I've not used Luna enough to judge whether it's significantly better than Luna, but at least via GitHub Copilot, Terra is leaps ahead of Sonnet 5.
So Luna is more awful but it's OK because it's cheaper?
I've had great success with using Luna and having DeepSeek 4 Flash check Luna's output. Oh My Pi has a mode built-in that does this automatically ("advisor" mode). Deepseek only interrupts when it spots an issue so it doesn't slow Luna down.
Both models are cheap enough that I can run 4 sessions at the same time without running out of the 20 USD codex and 10 USD Opencode plan. I've burned through almost a billion tokens this week and I've done some pretty big refactors as well.
I have a Claude Max subscription but I've barely been using it because of the many issues they've had this week.
Yes. You're better off running Luna Max or Sol Medium and never touching Terra.
I guess I should give it another shot because I had pretty bad experience with Luna when it first came out. Stuff Sonnet knew better.
Were free users subject to some limits? I've never run into any limits.
It used to be 10 messages every 5 hours using GPT-5, then unlimited 4o-mini. More recently, it went down to ~5 messages per day on 5.5 Instant, then unlimited on 5.5 mini.
While their math results are impressive, vibe coding their own web UIs with their subpar design models is really going to backfire if their plan is to attract new users with better free model offerings.
The Aug 6 update has forced the entry box to auto-format Markdown in an attempt to imitate Claude. The implementation is buggy and even simple copy-and-paste has gone entirely haywire. They also forgot to leave a switch to turn the confounded autoformatting thing off.
Chat mode in general is currently crawling with more UX bugs than a porch screen in summer.
>avoid extra detail when it does not help
I wonder if they actually do it to optimize inference. I maintain a corporate AI server and one of the tricks to reduce the load was to modify the system prompt to be as terse as possible so the average response completes faster and requests queue up less often.
This is actually a downgrade for free users since currently it uses GPT-5.5 for a few messages before it drops you down to GPT-5.5-mini. Now it always uses a model worse than Mini (Luna is nano-equivalent, "It roughly corresponds to the nano model tier used in earlier GPT-5 families." https://developers.openai.com/api/docs/models/gpt-5.6-luna ). I guess it's a bit better with Thinking though. They should use Terra for a few messages first before dropping down to Luna. And image inputs are still limited.
Expanding free access is mostly an inference cost
Serving cheaply at that scale means routing, batching, and cache hits, not a better model :D
> Our mission is to ensure that artificial general intelligence benefits all of humanity. We’re introducing updates to ChatGPT that improve everyday conversations while expanding access for Free users.
My mission is world conquest. I'm writing a comment on an HN thread.
No, those two clauses have no relation whatsoever. I just felt like saying the first sentence because it sounded cool.
Why pay for ChatGPT Go then?
Access to "ChatGPT-Image-2" I suppose?
Every week, 1 billion people turn to ChatGPT for everything from quick questions and web searches to planning, research, advice, and complex decisions.
[0] Won't put it past OpenAI (and/or Google) to open weight larger models!
$20/month also gives you API access for coding, in any coding agent. I keep hitting the weekly limit but it's a good deal while it lasts.
Google’s AI has been very glitchy for me lately. I used to reserve chatGPT for serious work and Gemini for daily personalized unimportant things. But now I switched completely to ChatGPT and resigned myself to their memories/personalization.
Did they do away with think? I think now you have to do it with /think
Does 5.6 Sol finally have an "instant" form? Is that the change?
Yes
At first I thought the Sol updates was perhaps trying to help with some complaints of Sol burning through tokens, complaints that have prompted some new data points on https://codex-resets.com/ .
But seeing the graphic with the visual weather report: that makes me think that is not the goal at all. :)
What a bizarre example of a more direct answer. Any human would simply say “No, it doesn’t rain here in summer.”
Even after identifying the 0% chance of rain, it still drags the conversation on and on and on
Would you like to know more? Seriously though, of course, it's tuned for maximum engagement, not maximum efficiency. I wonder how long this engagement dopamine circus can last... too long apparently.
GPT models were RLHF'd to death, they will never give a final, direct answer. Every release since the GPT-4o catastrophy is like this, it's so tiresome. They need a complete reset before it can become actually usable again. Or not as maximum engagement seems to be their goal.
I dont pay for a chatgpt subscription, but sometimes I did use the web app for throwaway questions. GPT 5.5 Instant or whatever it was that they had was absolutely horrendous. Never answered a question straight and was pedantic in a way even a redditor wouldn't be. So I dropped it and just opened my paid coding agent for everything. Grok.com is quite good now with grok 4.5 though and I find myself using that often. Hopefully luna will be similar.
a m-dash in the title? whoa things are degrading fast