I had quite a fun time getting those pelicans though... since GPT-5 Codex Mini isn't officially available via API yet I instead had OpenAI's Codex CLI tool extend itself (in Rust) to add a "codex prompt ..." tool which uses their existing custom auth scheme and backend API, then used that to generate the pelicans. Full details here: https://simonwillison.net/2025/Nov/9/gpt-5-codex-mini/
Can't believe I'm saying this, but GPT-5's pelican is its most impressive improvement over 4o I've seen. I wonder if Codex' MoE does not contain any expert fit for this task due to its fine-tuning on code.
I'll know if they do, because I'll notice that a new model is suspiciously great at drawing pelicans riding bicycles while still sucking at drawing other things.
Since they also limited the usage of codex CLI quite a bit, this might help. I really like the gpt-5-codex model. It has the most impressive dynamic reasoning effort I've seen. Responding instantly to simple questions while thinking very long when necessary. It's also interesting how close it is in many benchmarks to gpt-5. It's not just a good coding model. It's a great agentic model.
What I discovered is different models are simply just better at different things and it’s very hard to predict which one will be better than the others at a certain task. Thus no one has similar experiences as no one is doing the same things the same way ever.
I'm half way through writing a typescript to native code translator (via .Net) compiling a large enough subset of current code with a lot of help from GPT5 and Codex CLI. It has completely blown me away.
I'd like to give you a concrete example which stood out (from by now, dozens). I wanted d.ts files from the .Net Standard Libs. One immediately obvious problem is that .Net would allow classes/interfaces to be redefined if the generic type arity is different. For example, there can be SomeClass<int> and SomeClass<int, int> which are completely separate. TypeScript of course, wouldn't allow this - you can have one with all types defined, but it'd obviously be a mess.
I was stuck with (quite ugly):
const users = new List_1<User>(...);
instead of
const users = new List<User>(...);
So GPT comes up with this:
declare const __unspecified: unique symbol;
type __ = typeof __unspecified;
// Your arity-anchored delegates exist elsewhere:
// import("internal/System").Action_0
// import("internal/System").Action_1<T1>
// import("internal/System").Action_2<T1, T2>
// import("internal/System").Action_3<T1, T2, T3>
// ... up to 17
export type Action<
T1 = __, T2 = __, T3 = __, // ... continue through T17 = __
> =
[T1] extends [__] ? import("internal/System").Action_0 :
[T2] extends [__] ? import("internal/System").Action_1<T1> :
[T3] extends [__] ? import("internal/System").Action_2<T1, T2> :
/* next lines follow the same pattern … */
import("internal/System").Action_3<T1, T2, T3>;
This lets me write:
const a: Action<number> = (n) => {}; // OK (void)
const f: Func<number, string> = (s) => 20; // OK (string -> number)
A human could come up with this, of course. But doing this at scale (there are many such problems which crop up), would take a lot of effort. Btw I'm using Claude for the grunt work (because its faster), but GPT5 is doing all the architecture/thinking/planning/review.
It is just poor at designing a generic solution despite repeated requests to follow the design of existing alternatives (present in the same repro). It tended to plug holes in a broken architecture it came up with on its own instead of redesigning or trying to simplify its code to be able to keep it in its own head. TBH I suspect this might be limited purely by context length.
It produced fine(-ish) initial bits so a few tests would pass, but it dug itself a hole of introducing provenance and could not keep track of it properly. You can see it: https://github.com/lostmsu/ILGPU/tree/Vulkan-GPT-5-Stuck
TBH2: this was a huge request. But also there are already other backends it could just mirror.
For instance if you wrote a type to extend number to something like range<min,max> - obviously a toy - it would look very similar to what you’ve posted. So I’m struggling to see what the insight from the LLM is. Anytime one needs to iterate in TS, arity or otherwise, that is the technique to use…
> For instance if you wrote a type to extend number to something like range<min,max> - obviously a toy - it would look very similar to what you’ve posted.
Why would Range need a sentinel?
My point is that using a sentinel to bridge TypeScript's lack of generic arity-based specialization is a non-trivial problem. After you mentioned it, I looked for examples on Google and couldn't find anything that matches precisely.
I'm not claiming humans can't solve this, or that gpt5 invented something fundamentally new. My original point was about productivity at scale. Having a model apply the right solution across dozens of similar problems, rather than me manually figuring out each one.
I'd say this holds true for LLMs in general depending on your standards of interest, but Codex has blown Claude out of the water for me personally. It seems to have much better code "taste" than any other model.
The GPT5 family is the most intelligent model IMO. It's the only model that I have found that can refactor complex code and have the result be better than what came before it.
All "AI" providers cut corners in the models right now because the subsidized cost is unsustainable.
Grok's latest update made it far worse than the version right after the Grok-4 release. It makes outright mistakes now. Copilot has cut corners long ago. Google "AI" was always horrible.
The whole "AI" experiment was an outrageously expensive IP laundering parlor trick that is meeting economic realities now.
Charging developers $200/month for Claude Code and getting to a billion in ARR sounds like a pretty great business to be in to me, especially with this growth rate:
> Claude Code is reportedly close to generating $1 billion in annualized revenue, up from about $400 million in July.
Relative to its competitors, Anthropic seems to have a higher share of professional users paying premium subscriptions, which is probably more sustainable in the long term.
Anecdotally, a Max subscriber gets something like $100 worth of usage per day. The more people use Claude Code, the more Anthropic loses, so it sounds like a classical "selling a dollar for 85 cents" business to me.
As soon as users are confronted with their true API cost, the appearance of this being a good business falls apart. At the end of the day, there is no moat around large language models - OpenAI, Anthropic, Google, DeepSeek, Alibaba, Moonshot... any company can make a SOTA model if they wish, so in the long run it's guaranteed to be a race to the bottom where nobody can turn a profit.
> Anecdotally, a Max subscriber gets something like $100 worth of usage per day.
Where are you getting that number from?
Anthropic added quite strict limits on usage - visible from the /usage method inside Claude Code. I would be surprised if those limits turn out to still result in expensive losses for them.
This is just personal experience + reddit anecdotes. I've been using CC from day one (when API pricing was the only way to pay for CC), then I've been on the $20 Pro plan and am getting a solid $5+ worth of usage in each 5h session, times 5-10 sessions per week (so an overall 5-10x subsidy over one month.) And I extrapolated that $200 subscribers must be getting roughly 10x Pro's usage. I do feel the actual limit fluctuates each week as Claude Code engage in this new subsidy war with OAI Codex though.
My theory is this:
- we know from benchmarks that open-weight models like Deepseek R1 and Kimi K2's capabilities are not far behind SOTA GPT/Claude
- open-weight API pricing (e.g. on openrouter) is roughly 1/10~1/5 that of GPT/Claude
- users can more or less choose to hook their agent CLI/IDEs to either closed or open models
If these points are true, then the only reason people are primarily on CC & Codex plans is because they are subsidized by at least 5~10x. When confronted with true costs, users will quickly switch to the lowest inference cost vendor, and we get perfect competition + zero margin for all vendors.
The benchmarks lie. Go try coding full-time with R1 vs Codex or GPT-5 (in Codex). The latter is firmly preferred even by those who have no issue with budgeting tokens for their productivity.
So Misanthropic claims that 416666.66 software developers have bought their expensive $200 subscription when there are 4.4 million software developers in the US.
That sounds reasonable given that 10% of software developers are talkers that need someone to output something that looks like a deliverable.
We were however talking profits here, not revenue.
Presumably their "$1bn ARR from Claude Code" number isn't just the $200/month subscribers, they have $20/month and $100/month plans too, both of which their internal analytics could be crediting to Claude Code based on API usage patterns.
That $1bn number was in a paywalled Information article which was then re-reported by TechCrunch so the actual source of the number isn't clear. I'm assuming someone leaked to the Information, they appear to have some very useful sources.
I doubt this is just US developers - they've boasted about how successful they are in Europe recently too:
> Businesses across Europe are trusting Claude with their most important work. As a result, EMEA has become our fastest-growing region, with a run-rate revenue that has grown more than 9x in the past year.
Are you kidding me? Is there any one person giving better AI updates nowadays than Simonw? Back in the day, there used to be these EF Hutton commercials. There'd be some scene of a bunch of people. One person would say something like, “My broker says…” and another would respond, “Well, my broker is EF Hutton, and EF Hutton says…”. And the whole restaurant or whatever would get silent so they could hear what EF Hutton says. It was great!
I feel the same way about Simon Willison. He's a treasure!
Here's a few of those EF Hutton commercials for your viewing pleasure--
That's a very long-winded way of saying "it was subsidized so it could capture a large market segment, and now that's stopping", which is what SV companies have done since checks notes forever.
An LLM would have generated four pages on this topic in order to increase the token count!
LLMs are advertised for serious applications. I don't recall that CPUs generally hallucinate except for the FDIV bug. Or that AirBnB rents you apartments that don't exist in 30% of all cases. Or that Uber cars drive into a river during 20% of all rides.
Are we talking about economics, or about hallucinations?
"CPUs don't hallucinate" would be a reasonable argument if CPUs were an alternative to LLMs, which they aren't, so I'm not really sure what argument you're making there.
Seems like you're saying "a calculator makes fewer mistakes than an accountant", which is true, but I still pay an accountant to do my taxes, and not a calculator.
Not saying that you are completely wrong, but you could try to rephrase this to make a better conversation.
I agree that many new model versions are worse than the previous. But it is also related to base rules of the model - they try to please you and manipulate you to like them, way too much.
Looks like a leak: https://platform.openai.com/docs/models does not list it, and codex-mini-latest says that it's based on 4o. I wonder if it will be faster than codex; gpt-5-nano and -mini are still very slow for me on API, surprisingly so.
I noticed the same thing with -mini. It can be even slower than the full fat version. I'm guessing their infra for it is very cost-optimized to help them offer it at such a low price
I managed to get GPT-5-Codex-Mini to draw me a pelican. It's not a very good one! https://static.simonwillison.net/static/2025/codex-hacking-m...
For comparison, here's GPT-5-Codex (not mini) https://static.simonwillison.net/static/2025/codex-hacking-d... and full GPT-5: https://static.simonwillison.net/static/2025/codex-hacking-g...
I had quite a fun time getting those pelicans though... since GPT-5 Codex Mini isn't officially available via API yet I instead had OpenAI's Codex CLI tool extend itself (in Rust) to add a "codex prompt ..." tool which uses their existing custom auth scheme and backend API, then used that to generate the pelicans. Full details here: https://simonwillison.net/2025/Nov/9/gpt-5-codex-mini/
Can't believe I'm saying this, but GPT-5's pelican is its most impressive improvement over 4o I've seen. I wonder if Codex' MoE does not contain any expert fit for this task due to its fine-tuning on code.
Make sure you check GPT-5.1’s from a couple days ago
Just curious, do you think LLM makers are deliberately adding training data for your pelican test by now?
I'll know if they do, because I'll notice that a new model is suspiciously great at drawing pelicans riding bicycles while still sucking at drawing other things.
Since they also limited the usage of codex CLI quite a bit, this might help. I really like the gpt-5-codex model. It has the most impressive dynamic reasoning effort I've seen. Responding instantly to simple questions while thinking very long when necessary. It's also interesting how close it is in many benchmarks to gpt-5. It's not just a good coding model. It's a great agentic model.
Codex isn’t even a good model.
It's been praised here. However in my experience Sonnet4.5 has produced as good if not better results.
What I discovered is different models are simply just better at different things and it’s very hard to predict which one will be better than the others at a certain task. Thus no one has similar experiences as no one is doing the same things the same way ever.
Based on what? It’s been great for me.
[flagged]
GPT-5 and GPT-5-Codex are already not clever enough for anything interesting.
What's your definition of interesting?
I'm half way through writing a typescript to native code translator (via .Net) compiling a large enough subset of current code with a lot of help from GPT5 and Codex CLI. It has completely blown me away.
I'd like to give you a concrete example which stood out (from by now, dozens). I wanted d.ts files from the .Net Standard Libs. One immediately obvious problem is that .Net would allow classes/interfaces to be redefined if the generic type arity is different. For example, there can be SomeClass<int> and SomeClass<int, int> which are completely separate. TypeScript of course, wouldn't allow this - you can have one with all types defined, but it'd obviously be a mess.
I was stuck with (quite ugly): const users = new List_1<User>(...); instead of const users = new List<User>(...);
So GPT comes up with this:
This lets me write: A human could come up with this, of course. But doing this at scale (there are many such problems which crop up), would take a lot of effort. Btw I'm using Claude for the grunt work (because its faster), but GPT5 is doing all the architecture/thinking/planning/review.I actually also used it on .NET codebase, specifically https://github.com/m4rs-mt/ILGPU
It is just poor at designing a generic solution despite repeated requests to follow the design of existing alternatives (present in the same repro). It tended to plug holes in a broken architecture it came up with on its own instead of redesigning or trying to simplify its code to be able to keep it in its own head. TBH I suspect this might be limited purely by context length.
It produced fine(-ish) initial bits so a few tests would pass, but it dug itself a hole of introducing provenance and could not keep track of it properly. You can see it: https://github.com/lostmsu/ILGPU/tree/Vulkan-GPT-5-Stuck
TBH2: this was a huge request. But also there are already other backends it could just mirror.
Couldn't you just replace `__` with `never`?
Ternary chains are pretty common in TS, since it’s the main control flow. Are you a comfortable TS user normally?
I'm a somewhat comfortable TS user.
Are you saying ternary chains using sentinels for arity inference is pretty common? I would disagree.
> since it’s the main control flow
Perhaps you're saying ternery chains are common in TS code? That's a very different thing though - the code above is not for runtime behavior.
For instance if you wrote a type to extend number to something like range<min,max> - obviously a toy - it would look very similar to what you’ve posted. So I’m struggling to see what the insight from the LLM is. Anytime one needs to iterate in TS, arity or otherwise, that is the technique to use…
> For instance if you wrote a type to extend number to something like range<min,max> - obviously a toy - it would look very similar to what you’ve posted.
Why would Range need a sentinel?
My point is that using a sentinel to bridge TypeScript's lack of generic arity-based specialization is a non-trivial problem. After you mentioned it, I looked for examples on Google and couldn't find anything that matches precisely.
I'm not claiming humans can't solve this, or that gpt5 invented something fundamentally new. My original point was about productivity at scale. Having a model apply the right solution across dozens of similar problems, rather than me manually figuring out each one.
What is a sentinel?
I'd say this holds true for LLMs in general depending on your standards of interest, but Codex has blown Claude out of the water for me personally. It seems to have much better code "taste" than any other model.
not correct. are you using high reasoning? i am using codex everyday.
What sort of stuff are you using it for?
computer vision things these days.
Medium reportedly uses even higher reasoning than high, when it chooses to. Whereas high is fixed at a high but not as high level.
The GPT5 family is the most intelligent model IMO. It's the only model that I have found that can refactor complex code and have the result be better than what came before it.
All "AI" providers cut corners in the models right now because the subsidized cost is unsustainable.
Grok's latest update made it far worse than the version right after the Grok-4 release. It makes outright mistakes now. Copilot has cut corners long ago. Google "AI" was always horrible.
The whole "AI" experiment was an outrageously expensive IP laundering parlor trick that is meeting economic realities now.
Charging developers $200/month for Claude Code and getting to a billion in ARR sounds like a pretty great business to be in to me, especially with this growth rate:
> Claude Code is reportedly close to generating $1 billion in annualized revenue, up from about $400 million in July.
https://techcrunch.com/2025/11/04/anthropic-expects-b2b-dema...
Relative to its competitors, Anthropic seems to have a higher share of professional users paying premium subscriptions, which is probably more sustainable in the long term.
Anecdotally, a Max subscriber gets something like $100 worth of usage per day. The more people use Claude Code, the more Anthropic loses, so it sounds like a classical "selling a dollar for 85 cents" business to me.
As soon as users are confronted with their true API cost, the appearance of this being a good business falls apart. At the end of the day, there is no moat around large language models - OpenAI, Anthropic, Google, DeepSeek, Alibaba, Moonshot... any company can make a SOTA model if they wish, so in the long run it's guaranteed to be a race to the bottom where nobody can turn a profit.
> Anecdotally, a Max subscriber gets something like $100 worth of usage per day.
Where are you getting that number from?
Anthropic added quite strict limits on usage - visible from the /usage method inside Claude Code. I would be surprised if those limits turn out to still result in expensive losses for them.
This is just personal experience + reddit anecdotes. I've been using CC from day one (when API pricing was the only way to pay for CC), then I've been on the $20 Pro plan and am getting a solid $5+ worth of usage in each 5h session, times 5-10 sessions per week (so an overall 5-10x subsidy over one month.) And I extrapolated that $200 subscribers must be getting roughly 10x Pro's usage. I do feel the actual limit fluctuates each week as Claude Code engage in this new subsidy war with OAI Codex though.
My theory is this:
- we know from benchmarks that open-weight models like Deepseek R1 and Kimi K2's capabilities are not far behind SOTA GPT/Claude
- open-weight API pricing (e.g. on openrouter) is roughly 1/10~1/5 that of GPT/Claude
- users can more or less choose to hook their agent CLI/IDEs to either closed or open models
If these points are true, then the only reason people are primarily on CC & Codex plans is because they are subsidized by at least 5~10x. When confronted with true costs, users will quickly switch to the lowest inference cost vendor, and we get perfect competition + zero margin for all vendors.
The benchmarks lie. Go try coding full-time with R1 vs Codex or GPT-5 (in Codex). The latter is firmly preferred even by those who have no issue with budgeting tokens for their productivity.
So Misanthropic claims that 416666.66 software developers have bought their expensive $200 subscription when there are 4.4 million software developers in the US.
That sounds reasonable given that 10% of software developers are talkers that need someone to output something that looks like a deliverable.
We were however talking profits here, not revenue.
Presumably their "$1bn ARR from Claude Code" number isn't just the $200/month subscribers, they have $20/month and $100/month plans too, both of which their internal analytics could be crediting to Claude Code based on API usage patterns.
That $1bn number was in a paywalled Information article which was then re-reported by TechCrunch so the actual source of the number isn't clear. I'm assuming someone leaked to the Information, they appear to have some very useful sources.
I doubt this is just US developers - they've boasted about how successful they are in Europe recently too:
> Businesses across Europe are trusting Claude with their most important work. As a result, EMEA has become our fastest-growing region, with a run-rate revenue that has grown more than 9x in the past year.
https://www.anthropic.com/news/new-offices-in-paris-and-muni...
[flagged]
Are you kidding me? Is there any one person giving better AI updates nowadays than Simonw? Back in the day, there used to be these EF Hutton commercials. There'd be some scene of a bunch of people. One person would say something like, “My broker says…” and another would respond, “Well, my broker is EF Hutton, and EF Hutton says…”. And the whole restaurant or whatever would get silent so they could hear what EF Hutton says. It was great!
I feel the same way about Simon Willison. He's a treasure!
Here's a few of those EF Hutton commercials for your viewing pleasure--
https://youtu.be/2MXqb1a3Apg
https://youtu.be/sc2GpmLx82k
Yep, that's how I feel when Simon Willison speaks!
That's a very long-winded way of saying "it was subsidized so it could capture a large market segment, and now that's stopping", which is what SV companies have done since checks notes forever.
An LLM would have generated four pages on this topic in order to increase the token count!
LLMs are advertised for serious applications. I don't recall that CPUs generally hallucinate except for the FDIV bug. Or that AirBnB rents you apartments that don't exist in 30% of all cases. Or that Uber cars drive into a river during 20% of all rides.
Are we talking about economics, or about hallucinations?
"CPUs don't hallucinate" would be a reasonable argument if CPUs were an alternative to LLMs, which they aren't, so I'm not really sure what argument you're making there.
Seems like you're saying "a calculator makes fewer mistakes than an accountant", which is true, but I still pay an accountant to do my taxes, and not a calculator.
I was obviously responding to your "SV companies have been doing that forever". You have introduced the general topic.
I don't see how CPU bugs have anything to do with subsidizing a product to capture market share, can you elaborate?
Certainly!
Thinking ...
- The user is asking about the connection between CPU bugs and price dumping in order to capture market share.
- The user appears to miss the original thread starter that mentions cutting corners in models after the subsidy phase is over.
- The mention of CPUs, AirBnB and Uber appear to be examples where certain quality standards were usually kept even after the subsidy phase.
Generating response ...
if you don't want hallucinations:
- set temp to 0
- be more specific
But I'd argue that if your LLM isn't hallucinating, then it's useless
How would setting temp to 0 preclude hallucinations?
It wouldn’t
The Chinese open source models don't have this problem -- and they're state of the art!
Not saying that you are completely wrong, but you could try to rephrase this to make a better conversation.
I agree that many new model versions are worse than the previous. But it is also related to base rules of the model - they try to please you and manipulate you to like them, way too much.
If any open AI devs reading this comment section: is it possible for us to get api access at runable.com ?
Looks like a leak: https://platform.openai.com/docs/models does not list it, and codex-mini-latest says that it's based on 4o. I wonder if it will be faster than codex; gpt-5-nano and -mini are still very slow for me on API, surprisingly so.
They announced it on Twitter yesterday: https://x.com/OpenAIDevs/status/1986861734619947305 and https://x.com/OpenAIDevs/status/1986861736041853368
> GPT-5-Codex-Mini allows roughly 4x more usage than GPT-5-Codex, at a slight capability tradeoff due to the more compact model.
> Available in the CLI and IDE extension when you sign in with ChatGPT, with API support coming soon.
I noticed the same thing with -mini. It can be even slower than the full fat version. I'm guessing their infra for it is very cost-optimized to help them offer it at such a low price
Yeah in my mind it was smaller -> faster. But seems like it might be 'a bit smaller and batched' to hit the price target.
They also just announced that they’re giving Pro tier prioritized access to Codex models. Are you on Pro? If not you might be getting deprioritized.