Cursor has confirmed that its latest coding AI, 'Composer 2,' is based on Kimi, a product of China's Moonshot AI.



On March 19, 2026, the coding AI ' Cursor ' announced its latest AI model, ' Composer 2. ' Composer 2 boasts cutting-edge coding performance while also being very cost-effective. However, after its release, users pointed out that 'Composer 2 is simply Kimi 2.5 with added reinforcement learning (RL),' and Cursor was forced to admit that Composer 2 is indeed a Kimi-based AI model.

Cursor admits its new coding model was built on top of Moonshot AI's Kimi | TechCrunch
https://techcrunch.com/2026/03/22/cursor-admits-its-new-coding-model-was-built-on-top-of-moonshot-ais-kimi/

After Composer 2 was released, X (formerly Twitter) user Fynn posted, 'While messing around with OpenAI's base URL in Cursor, I found this: 'accounts/anysphere/models/kimi-k2p5-rl-0317-s515-fast'. In other words, it seems Composer 2 is just a Kimi K2.5 with reinforcement training applied. At the very least, they should have changed the model ID name,' pointing out that the code contains the string 'kimi-k2p5'.




Technology media outlet TechCrunch points out, 'Cursor is a well-funded American AI startup that just raised $2.3 billion (approximately 370 billion yen) in the fall of 2025, with a valuation of $29.3 billion (approximately 4.67 trillion yen). This is surprising, as it has been reported that its annual revenue exceeds $2 billion (approximately 320 billion yen). Cursor made no mention of Moonshot AI or Kimi in its announcement of Composer 2.'

Lee Robinson, Vice President of Developer Education at Cursor, responded to this post as follows:

'Composer 2 started on an open-source base! In the future, we will implement full pre-training . Only about a quarter of the computing resources used for the final model come from the base open-source AI model, with the rest coming from our own training. This is why evaluation results vary so much. And we adhere to licenses through inference partner agreements.'




'I'll say it because it seems like people want me to say it. The underlying AI model is 'KIMI K2.5'. That's the base AI model we used. Of course, we comply with the license through the terms of our inference partnership. Personally, I'm grateful for open-source software models. They're great for the ecosystem.'




'We've received confirmation from the Kimi team that they are complying with the license. However, we agree with the user feedback. We should have mentioned the underlying AI model from the beginning. We will do so in the next model!'




The official Kimi post that Robinson quoted is below:

'Congratulations on the launch of Composer 2. We are proud to see Kimi-k2.5 providing the foundation. Seeing our model effectively integrated through Cursor's continuous pre-training and high-computational-reinforcement learning is exactly the kind of open model ecosystem we are eager to support. Cursor accesses Kimi-k2.5 via the reinforcement learning and inference platform hosted by Fireworks AI , which is part of an authorized commercial partnership.'




TechCrunch explains why Cursor didn't admit to using Kimi from the beginning: 'Aside from the potential embarrassment of not building an AI model from scratch, given that the so-called AI arms race is often seen as a battle for survival between the US and China, building on a Chinese AI model might seem particularly difficult.'

Furthermore, Cursor co-founder Aman Sanger also stated on X that it was a mistake not to acknowledge that Composer 2 is Kimi-based.




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