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.

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].

[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=...

"Just" Kimi K2.5 with RL—people really misunderstand how difficult it is to achieve these reults with RL. Cursor's research team is highly respected within the industry, and what they've done is quite impressive.

Before people go jumping to conclusions about model theft, it's worth considering the possibility that they did reach an agreement with Moonshot which their researchers were not aware of. That would certainly explain the deleted tweets. Until Moonshot makes an official statement, I'm not particularly concerned.

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.

Partnership confirmed by Moonshot:

Cursor accesses Kimi-k2.5 via FireworksAI_HQ hosted RL and inference platform as part of an authorized commercial partnership.

https://x.com/Kimi_Moonshot/status/2035074972943831491

Cursor teams take:

Only ~1/4 of the compute spent on the final model came from the base, the rest is from our training. This is why evals are very different.

https://x.com/leerob/status/2035035355364081694

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.

They’re pretty upfront in their release post that they took an open source model and improved it with their own coding data. They mention “continued pretraining” (on top of the base model) and RL. Cursor never claimed to have done a full pretraining run.

More to the point, beating Opus 4.6 at coding and coming within striking distance of gpt-5.4 is impressive! The benchmarks outperform raw Kimi K2.5.

It’s particularly impressive given larger labs like Meta are struggling to catch up to OpenAI/Anthropic.

This is exactly what Cursor should be doing, within the obvious bounds of the law and such. Not everyone needs a pristine foundation model. What a waste of compute. Anthropic & OpenAI need product-level competition to knock them off their $25/Mtok horse.

There's no "just" in RL. Fine tuning is very important and could make a lot of difference.

im pretty sure this is in violation of moonshot's ToS. this is going to be fun to watch unfold

The cursor investor pitch was we're training our own models to do coding. If your amazing model is just an RL repack, you need a new pitch to justify your 50bn valuation

https://www.bloomberg.com/news/articles/2026-03-12/ai-coding...

What does this mean, that you can take Kimi and RL finetune it a little more and blow the big AI shops out of the water?

Would this have been extensively fine tuned, beyond what Anthropic/OAI would do themselves?

I guess this is Cursor's own benchmark, so you can finetune on your own dataset and get better results on your own specific tasks I guess.

Advertising your model with some obviously home grown benchmark is a bold play. It doesn't matter how good your model is, I immediately trust it less.

To be fair, is "with RL", "just"?

They should have disclosed it though. If they didn't it's a bad look for sure.

FYI: Someone from Cursor has responded to this https://x.com/leerob/status/2035035355364081694

I think there's a reason why the people from Moonshot deleted their tweets; they're probably just researchers who got yelled at by the people who actually knew what was going on at Moonshot.

Moonshot is raising money at a 10B usd valuation, cursor/anysphere is at a 30B usd valuation.

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.

This is actually becoming a path dependency, a dependence on the supply chain.

What do people like about cursor? I've been using it for the past couple days, and I just don't see many positive things about it. It seems people like the autocomplete so I'll have to give that a try.

There's just too many "features" the ux ends up being all over the place. I thought having the browser inside of the editor would be great for design, but it's not that much better than just having your browser open along with your editor.

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.

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?

Scores higher than Opus 4.6 on their in-house benchmark? Sounds legit.

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?

cursor copy open source software repack it as closed source and made massive money. i don't want to hear anything on how Chinese is stealing and copying when the west is doing it themselves.

This whole ai stuff feels like a big bubble especially with the oil price soon at $200 and guaranteed recession.

Honestly, this is pretty much how most of the new models operate nowadays: a base model combined with RL and some product-layer magic.

Their first model was also based on an open source Chinese base model. They never fully trained their own model.

is this the model used on free mode?

I noticed something strange with Cursor lately. When I am using Opus 4.6, sometimes it is giving ridiculously dumb answers as if they were actually using something like Qwen with a prompt to present itself as Opus. I have to close the session and start again hoping I'll get actual Opus.

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).

YC is back at it again.

I whish it was GLM 5.0.

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).

[0] https://www.anthropic.com/news/detecting-and-preventing-dist...

Cursor can't compete with Claude Code's subsidized pricing, so they are trying to gaslight people that their cheap model is good enough.

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.

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A hyped startup providing zero added value, burning investor money only to repackage somebody else's work? That's new... /s