Cursor Composer 1 was Qwen and this is Kimi. IDE is based on VSCode. The entire company is build on packaging open source and reselling it.
Ollama is also doing this.
There is so much money to be made repackaging open source these days.
So funny to see Twitter go wild saying "a 50 person team just beat Anthropic" blah blah.
NitpickLawyer 2 hours ago [-]
> packaging open source and reselling it.
It's a bit more than that. They have plenty of data to inform any finetunes they make. I don't know how much of a moat it will turn out to be in practice, but it's something. There's a reason every big provider made their own coding harness.
pbowyer 2 hours ago [-]
Can anyone enlighten me how having a coding harness when for most customers you say "we won't train on your code" helps you do RL? What's the data that they rely on? Is it the prompts and their responses?
rubymamis 2 hours ago [-]
I guess they rely on many people not toggling privacy-mode on?
victorbjorklund 2 hours ago [-]
I doubt the majority does that. I bet the majority is using the defaults.
rubymamis 2 hours ago [-]
Do you know what Qwen model Composer 1.5 used?
rvz 54 minutes ago [-]
> Cursor Composer 1 was Qwen...
We know Composer 2 is Kimi K2.5 from that tweet. Where is the evidence for Composer 1 being based on Qwen?
> So funny to see Twitter go wild saying "a 50 person team just beat Anthropic" blah blah.
In this case, it will be the other way round: Anthropic will see Cursor as a competitor AI lab using open weight models for Composor 2 (actually Kimi K2.5) which was allegedly distilled from Opus 4.6, and would be enough for Anthropic to cut off Cursor from using any of models.
That's where it is going.
deaux 3 hours ago [-]
Looks like two Moonshot employees confirmed that it's not licensed before Moonshot made the decision to get out of the debate and delete their posts [0][1].
TBH they really shouldn't have posted such a tweet in the first place, just sit back and watch their license enforced by the Internet.
I had the question "how do you even enforce this weird license term" back then, I guess I know the answer now.
lmc 3 hours ago [-]
This is on their website...
"Is Kimi K2.5 open source?"
"Yes, Kimi K2.5 is an open source AI model. Developers and researchers can explore its architecture, build new solutions, and experiment openly. Model weights and code are publicly available on Hugging Face and the official GitHub repository."
Our only modification part is that, if the Software (or any derivative works
thereof) is used for any of your commercial products or services that have
more than 100 million monthly active users, or more than 20 million US dollars
(or equivalent in other currencies) in monthly revenue, you shall prominently
display "Kimi K2.5" on the user interface of such product or service.
ffsm8 2 hours ago [-]
My first reaction was "well, who knows how much revenue they're actually doing"
But at least the rumor mill has them significantly above that line:
> Revenue: As of March 2026, reports suggest Cursor has surpassed $2 billion in annualized revenue (ARR).
You can't just add random terms to an existing license and use its name. "Modified MIT: Like MIT but pay us 50 million dollars."
Perhaps CC-BY would've been more appropriate.
igravious 6 minutes ago [-]
Correct again -- CC- applies to data, not code -- weights are data, open weights suggests a creative commons approach …
“
CC-BY 4.0
Creative Commons Attribution 4.0 International
This license requires that reusers give credit to the creator. It allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, even for commercial purposes.
BY
Credit must be given to you, the creator.
”
it's annoying the open source term is being cargo-culted around and I hate to say it but that ship looks like it has sailed.
funny that free software people were infuriated by the open source term and now the open source term is being completely misused in another context
bakugo 2 hours ago [-]
It wouldn't be regardless, because the model is open weights, not open source. It's just a license.
lmc 2 hours ago [-]
Which contradicts what they say on their website.
igravious 11 minutes ago [-]
Correct. (and I know you already know this but just for the record: (Nearly?) Everybody abuses the term "open source" when it comes to models. OSI have a post about it: https://opensource.org/ai/open-weights
gillesjacobs 3 hours ago [-]
Cursor is mostly an IDE / coding-agent harness company.
So it probably makes sense for them not to train their own base model, but instead license something like Kimi and fine-tune it for their own harness and workflows.
Their moat looks pretty thin. A VSCode fork with an open-source LLM fork on top. In the fast-moving coding-agent market, it’s not obvious they keep their massive valuation forever.
jstummbillig 3 hours ago [-]
There is a plausible scenario in which software engineering requires a very finite amount of intelligence, in which sota models will be used mainly for other things and where for coding the harness will become increasingly more important than the model.
NitpickLawyer 2 hours ago [-]
> Their moat looks pretty thin.
Their value is in the data they've collected and are collecting. Usage, acceptance rate, and all the connected signals. Plus having a large userbase where they can A / B test any finetune they create.
_puk 2 hours ago [-]
There were conversations in the team yesterday about how Cursor's cloud agents are still ahead of Claude from a UX perspective.
Obviously we're running both, using the right tool for the job.
There is stickiness there from being early. That will be hard to replicate.
CharlieDigital 2 hours ago [-]
That's every harness including VC Code Copilot.
People home about Teams sucking, but its market share is several times that of Slack because of distribution.
I guarantee that Microsoft has even more data.
prodigycorp 2 hours ago [-]
There are many reasons to make fun of Cursor. However, one of the things get right is their autocomplete model.
Are there any open models that come close? Why doesnt OAI or Anthropic dedicate some resources to blowing Cursor's model out of the water? Cursor's completion model is a sticking point for a lot of users.
seunosewa 1 hours ago [-]
Antigravity has an autocomplete model too. Based on Windsurf's, I guess.
olejorgenb 2 hours ago [-]
The model is great. The UX is horrible...
g947o 1 hours ago [-]
Most companies don't do auto competition these days, including some that just recently stopped offering completion.
Which I find very unfortunate. There are so many cases, especially in proprietary codebases with non standard infrastructure, where good autocomplete is much better than "agentic" edits that produce nothing but slop which takes longer to clean up.
simonw 16 minutes ago [-]
I'm annoyed that we still don't know for certain which base model they used for Cursor 1.
This feels really rude to me. I have no problem with them fine-tuning open weight models to create their own - they are getting great results, and Cursor's research term should be respected for that. But deliberately hiding the base model they use is disrespectful of the researchers who created that model.
justindotdev 3 hours ago [-]
im pretty sure this is in violation of moonshot's ToS. this is going to be fun to watch unfold
NitpickLawyer 3 hours ago [-]
There is no ToS at play here. There's only the license[1], which is MIT modified like so:
> Our only modification part is that, if the Software (or any derivative works
thereof) is used for any of your commercial products or services that have
more than 100 million monthly active users, or more than 20 million US dollars
(or equivalent in other currencies) in monthly revenue, you shall prominently
display "Kimi K2.5" on the user interface of such product or service.
Yes, this is pretty clear-cut. There's even a great alternative, namely GLM-5, that does not have such a clause (and other alternatives besides) so it feels a bit problematic that they would use Kimi 2.5 and then disregard that advertisement clause.
NitpickLawyer 2 hours ago [-]
I've replied down the thread, but there are ways to go around that clause entirely, even if it would be enforceable. The obvious way is to have another company do the modification.
zozbot234 2 hours ago [-]
The worthwhile question AIUI is whether AI weights are even protected by human copyright. Note that firms whose "core" value is their proprietary AI weights don't even need this (at least AIUI) since they always can fall back on "they are clearly protected against misappropriation, like a trade secret". It becomes more interesting wrt. openly available AI models.
kgeist 2 hours ago [-]
At the same time, Moonshot violated Anthropic's ToS by training on their models' outputs :) [0]. And Anthropic violated copyright law by training on copyrighted material. It's violations all the way down.
I thought Anthopoc’s training was deemed fair used. It was the downloading that was illegal
gillesjacobs 3 hours ago [-]
They probably licensed it. Still a bit deceptive not to mention it on the model card/blog post, but companies whitelabel all the time without mentioning.
It goes against the ML community ethos to obscure it, but is common branding practice.
deaux 3 hours ago [-]
No they didn't [0][1]. With this leak they're probably negotiating as we speak, which could be why they've deleted the posts.
Kimi K2.5 was released under a modified MIT license (100M+ MAU or $20M+ MRR has to prominently display Kimi K2.5). It will be fine.
antirez 3 hours ago [-]
Basically this is true for most startups in the world BUT Cursor, so here you are kinda inverting the logic of the matter. Cursor is at a size that, if they wanted to use K2.5, they could clearly state that it was K2.5 or get a license to avoid saying it.
NitpickLawyer 2 hours ago [-]
IF we assume that the modified MIT clause is enforceable. And if we assume Cursor Inc. is running the modification. It could very well be the case that Cursor Research LTD is doing the modifications and re-licensing it to Cursor Inc. That would make any clause in the modified MIT moot.
HeavyStorm 1 hours ago [-]
There's no "just" in RL. Fine tuning is very important and could make a lot of difference.
chvid 1 hours ago [-]
Moonshot is raising money at a 10B usd valuation, cursor/anysphere is at a 30B usd valuation.
Sammi 3 hours ago [-]
As a paying customer, it just doesn't feel good that they are trying to pass off someone else's model as their own.
I mean I guess this is what businesses do all the time. There's a term for it even, it's called white-labeling.
But is this all that Cursor have? They pass of VS Code as their own, they pass off Kimi as their own... What do Cursor even do? What do I need them for?
jstanley 3 hours ago [-]
As a paying customer, I don't care where the model comes from, I only care how good it is.
Sammi 3 hours ago [-]
Sure, and also at what price point.
But can I rely on Cursor to be able to keep delivering, when they aren't the one's doing the work themselves?
khuey 3 hours ago [-]
White-labeling may be slightly dishonest to the consumer but the manufacturer and distributor are honest with each other. That doesn't appear to be the case here (Kimi's license requires publicly acknowledging Kimi is used for anyone operating at Cursor's scale).
todteera 3 hours ago [-]
From a users perspective, do we really care what model we're using under the hood? Or how well the software is solving our problems?
Seems like cursor is trying to build a "thicker wrapper" beyond the harness. Either to protect against Anthropic shutting them off or increase margins.
EugeneOZ 16 minutes ago [-]
I don't know - it works okay (yet to be tested whether it is actually smarter than Opus 4.6), but it is not bad at all. So far, it works quite fine (I'm not testing the "fast" version).
vachina 2 hours ago [-]
A question. I’m due for a yearly Cursor subscription renewal, how does the credit limit look like?
Currently I’ve not hit any of the limits despite using it quite rigorously, I wonder if this will change with a renewal?
thewhitetulip 55 minutes ago [-]
But you have to buy into it right? If you don't have a limit then what did your contract look like?
taytus 41 minutes ago [-]
YC is back at it again.
olejorgenb 2 hours ago [-]
To be fair, is "with RL", "just"?
They should have disclosed it though. If they didn't it's a bad look for sure.
samsudin 2 hours ago [-]
[dead]
cbg0 2 hours ago [-]
Scores higher than Opus 4.6 on their in-house benchmark? Sounds legit.
mono442 2 hours ago [-]
This whole ai stuff feels like a big bubble especially with the oil price soon at $200 and guaranteed recession.
lossolo 3 hours ago [-]
Their first model was also based on an open source Chinese base model. They never fully trained their own model.
DeathArrow 2 hours ago [-]
I whish it was GLM 5.0.
koakuma-chan 2 hours ago [-]
Cursor can't compete with Claude Code's subsidized pricing, so they are trying to gaslight people that their cheap model is good enough.
heliumtera 2 hours ago [-]
For all the muh productivity guys that like to claim they can turn invisible when no one is looking, an produce 600k lock over 6 weeks, well...cursor is useless now. We know kimi K2.5 won't make you 100 trillion times faster.
Cursor is killed for this market.
rvz 3 hours ago [-]
Honestly I don't think this leak is any good for Cursor. Not only this appears as a violation to Moonshot's ToS, this may also be in fact enough evidence for Anthropic to ban Cursor from using their models, just like they are doing to OpenCode.
Why? As I said before, Anthropic mentions Moonshot AI (Maker of the Kimi models) as one of the AI labs that were part of this alleged "distillation attack" [0] campaign and will use that reason to cut off Cursor, Just like they did to OpenAI, xAI and OpenCode.
Let's see if the market thinks Composor 2 is really that good without the Claude models helping Cursor. (If Anthropic cuts them off).
Ollama is also doing this.
There is so much money to be made repackaging open source these days.
So funny to see Twitter go wild saying "a 50 person team just beat Anthropic" blah blah.
It's a bit more than that. They have plenty of data to inform any finetunes they make. I don't know how much of a moat it will turn out to be in practice, but it's something. There's a reason every big provider made their own coding harness.
We know Composer 2 is Kimi K2.5 from that tweet. Where is the evidence for Composer 1 being based on Qwen?
> So funny to see Twitter go wild saying "a 50 person team just beat Anthropic" blah blah.
In this case, it will be the other way round: Anthropic will see Cursor as a competitor AI lab using open weight models for Composor 2 (actually Kimi K2.5) which was allegedly distilled from Opus 4.6, and would be enough for Anthropic to cut off Cursor from using any of models.
That's where it is going.
[0] https://chainthink.cn/zh-CN/news/113784276696010804 - may have originally been https://x.com/apples_jimmy/status/2034920082602864990
[1] https://pbs.twimg.com/media/HD2Ky9jW4AAAe0Y?format=jpg&name=...
I had the question "how do you even enforce this weird license term" back then, I guess I know the answer now.
"Is Kimi K2.5 open source?"
"Yes, Kimi K2.5 is an open source AI model. Developers and researchers can explore its architecture, build new solutions, and experiment openly. Model weights and code are publicly available on Hugging Face and the official GitHub repository."
https://www.kimi.com/ai-models/kimi-k2-5
Our only modification part is that, if the Software (or any derivative works thereof) is used for any of your commercial products or services that have more than 100 million monthly active users, or more than 20 million US dollars (or equivalent in other currencies) in monthly revenue, you shall prominently display "Kimi K2.5" on the user interface of such product or service.
But at least the rumor mill has them significantly above that line:
> Revenue: As of March 2026, reports suggest Cursor has surpassed $2 billion in annualized revenue (ARR).
You can't just add random terms to an existing license and use its name. "Modified MIT: Like MIT but pay us 50 million dollars."
Perhaps CC-BY would've been more appropriate.
“ CC-BY 4.0 Creative Commons Attribution 4.0 International
This license requires that reusers give credit to the creator. It allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, even for commercial purposes.
BY Credit must be given to you, the creator. ”
it's annoying the open source term is being cargo-culted around and I hate to say it but that ship looks like it has sailed.
funny that free software people were infuriated by the open source term and now the open source term is being completely misused in another context
Their moat looks pretty thin. A VSCode fork with an open-source LLM fork on top. In the fast-moving coding-agent market, it’s not obvious they keep their massive valuation forever.
Their value is in the data they've collected and are collecting. Usage, acceptance rate, and all the connected signals. Plus having a large userbase where they can A / B test any finetune they create.
Obviously we're running both, using the right tool for the job.
There is stickiness there from being early. That will be hard to replicate.
People home about Teams sucking, but its market share is several times that of Slack because of distribution.
I guarantee that Microsoft has even more data.
Are there any open models that come close? Why doesnt OAI or Anthropic dedicate some resources to blowing Cursor's model out of the water? Cursor's completion model is a sticking point for a lot of users.
Which I find very unfortunate. There are so many cases, especially in proprietary codebases with non standard infrastructure, where good autocomplete is much better than "agentic" edits that produce nothing but slop which takes longer to clean up.
This feels really rude to me. I have no problem with them fine-tuning open weight models to create their own - they are getting great results, and Cursor's research term should be respected for that. But deliberately hiding the base model they use is disrespectful of the researchers who created that model.
> Our only modification part is that, if the Software (or any derivative works thereof) is used for any of your commercial products or services that have more than 100 million monthly active users, or more than 20 million US dollars (or equivalent in other currencies) in monthly revenue, you shall prominently display "Kimi K2.5" on the user interface of such product or service.
[1] - https://huggingface.co/moonshotai/Kimi-K2.5/blob/main/LICENS...
https://news.ycombinator.com/item?id=47126614
It goes against the ML community ethos to obscure it, but is common branding practice.
[0] https://chainthink.cn/zh-CN/news/113784276696010804
[1] https://pbs.twimg.com/media/HD2Ky9jW4AAAe0Y?format=jpg&name=...
I mean I guess this is what businesses do all the time. There's a term for it even, it's called white-labeling.
But is this all that Cursor have? They pass of VS Code as their own, they pass off Kimi as their own... What do Cursor even do? What do I need them for?
But can I rely on Cursor to be able to keep delivering, when they aren't the one's doing the work themselves?
Seems like cursor is trying to build a "thicker wrapper" beyond the harness. Either to protect against Anthropic shutting them off or increase margins.
Currently I’ve not hit any of the limits despite using it quite rigorously, I wonder if this will change with a renewal?
They should have disclosed it though. If they didn't it's a bad look for sure.
Cursor is killed for this market.
Why? As I said before, Anthropic mentions Moonshot AI (Maker of the Kimi models) as one of the AI labs that were part of this alleged "distillation attack" [0] campaign and will use that reason to cut off Cursor, Just like they did to OpenAI, xAI and OpenCode.
Let's see if the market thinks Composor 2 is really that good without the Claude models helping Cursor. (If Anthropic cuts them off).
[0] https://www.anthropic.com/news/detecting-and-preventing-dist...