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Cursor Composer 2 is just Kimi K2.5 with RL

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Re: Cursor Composer 2 is just Kimi K2.5 with RL

#101

Post by enraged_camel »

simonw wrote: post #63

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.

Simon, sorry to hijack the thread, but what is a good way of contacting you? I'd love to pick your brain on an AI talk I'm supposed to be giving soon.

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#102

Post by nsingh2 »

lubujackson wrote: post #86
bearjaws wrote: post #81

Earlier quoted context omitted.

As a command line junkie, what is the main thing Claude Code needs to catch up with cursor? I haven't dove into using a LLM in my editor, so I am less familiar with workflows there.

I use both pretty heavily. Cursor has an "Ask" mode that is useful when I don't want it to touch files or ask a non-sequitur. Claude may have an easy way to do this, but I haven't seeked it. Cursor also has an interesting Debug mode that actively adds specific debug logging logic to your code, runs through several hypotheses in a loop to narrow down the cause, then cleans up the logging. It can be super useful. Final…

The majority of Ask/Debug mode can be reproduced using skills. For copying code references, if you're using VS Code, you can look at plugins like [1], or even make your own.

Cursor's auto mode is flaky because you don't know which model they're routing you to, and it could be a smaller, worse model.

It's hard to see why paying a middleman for access to models would be cheaper than going directly to the model providers. I was a heavy Cursor user, and I've completely switched to Codex CLI or Claude Code. I don't have to deal with an older, potentially buggier version of VS Code, and I also have the option of not using VS Code at all.

One nice thing about Cursor is its code and documentation embedding. I don't know how much code embedding really helps, but documentation embedding is useful.

[1] https://marketplace.visualstudio.com/items?itemName=ezforo.c...

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#104

Post by acmj »

Sammi wrote: post #4
jstanley wrote: post #3

Earlier quoted context omitted.

As a paying customer, I don't care where the model comes from, I only care how good it is.

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?

Well, they can keep stealing as long as someone open weight their models.

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#105

Post by happyopossum »

doctorpangloss wrote: post #78
pbowyer wrote: post #36

Earlier quoted context omitted.

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?

It doesn't matter what your privacy setting is, with any savvy vendor. Your data is used to train by paraphrasing it, and the paraphrasing makes it impossible to prove it was your data (it is stored at rest paraphrased). Of course the paraphrasing stores all the salient information, like your goals and guidance to the bot to the answer, even if it has no PII.

That's an interesting accusation there! You're essentially accusing every "savvy vendor" of large-scale fraud... DOn't suppose you'd have any actual citations or evidence to back that up?

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#106

Post by simplyluke »

mohsen1 wrote: post #22

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.

> a 50 person team just beat Anthropic

How does this blow that narrative up? A 50 person team likely broke a license to have a product that's competitive on output at a fraction of the costs of one of the most well capitalized companies on the planet. Claude code and anthropic are certainly the darlings of the space today, but to me this just reinforces the idea that their moat is razor thin on the model front, even compared to OSS that can be run on independent hardware.

The application layer play is also suspect to me. In the medium to long term I _want_ tools that'll let me run whatever models I want vs being tied to an expensive, proprietary, and singular provider. For personal work I care about costs, and eventually my employer will care both about costs _and_ enterprise features/governance that a company like Anysphere is extremely well positioned to provide.

More and more, I see the future of the application layer being model agnostic, most enterprises hosting models on their own cloud for data security concerns, and the models being fully commoditized.

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#107

Post by Tadpole9181 »

olejorgenb wrote: post #49
prodigycorp wrote: post #43

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.

The model is great. The UX is ~~horrible~~ annoying...

Don't get me started. For every half-decent choice, there's a multitude of insane choices. After all this time they still don't have side-by-side review.

Equally as annoying, the break from VSCode is horrible. Having to use a separate registry, not having basic settings sync, the delay behind mainline VSCode updates.

Then, it's just plain buggier than others. The agent terminal just doesn't work semi-regularly, it doesn't like listing directories in the @, the SSH plugin crashes every other time it tries to connect, undoing agent work undoes edits I made in unrelated files sometimes. Sometimes updates just regress performance hard for seemingly no reason.

I also noticed the token use is wildly less efficient than CC or Codex these days. After almost no time at all it's up to 100,000 tokens and they're charging $1 per request for Sonnet. Side-by-side, Cursor spent $17 in the same time CC spent $4. Which is bizarre to me, since they advertise how their indexing and semantic search is more token efficient?

The autocomplete model was the only reason I stayed as long as I did. I wish there was a VSCode equivalent.

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#108

Post by elashri »

chzblck wrote: post #79
miroljub wrote: post #72

Earlier quoted context omitted.

> 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. The question is, where's the outrage? Why are there no headlines "USA steals Chinese tech?" "All USA can do is make a cheap copy of Chinese SOTA models". > So funny to see Twitter go wild saying "a 50 person team just beat Anthropic" blah blah. Well, if it's an American company…

because its open source.

Open source licence requires attribution which obviously it is not done in this case.

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#109

Post by simplyluke »

htrp wrote: post #97

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...

Any investor who believed a team their size and with their capital was training a SOTA base model doesn't understand the space. I fully believe that was some of their investors, but people acting like RL + fine tuning based on their massive user base that's producing qualitatively better outputs than the base model is meaningless aren't understanding what the company is doing.

Re: Cursor Composer 2 is just Kimi K2.5 with RL

#110

Post by aimarketintel »

mohsen1 wrote: post #22

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.

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