Artificial intelligence startup Cursor has confirmed that its newly released coding model, Composer 2, was partially built on an existing open-source framework.

The admission follows online speculation suggesting similarities between Composer 2 and Kimi 2.5, a model developed by Chinese firm Moonshot AI. The controversy emerged after users identified technical markers within the model that appeared to reference Kimi.

This raised questions about transparency, especially given Cursor’s positioning of the model as offering cutting-edge coding intelligence. The company had not initially disclosed any connection to the open-source system.

In response, Cursor’s leadership clarified that while the model began with an open-source base, the majority of its development involved proprietary training and computational investment.

Executives emphasized that Composer 2 has since evolved significantly, producing performance outcomes distinct from its original foundation.
The company also stated that its use of the base model complies with licensing agreements and forms part of a legitimate commercial partnership.
Cursor acknowledged, however, that failing to disclose the foundation earlier was an oversight and pledged greater transparency in future releases.

Source: TechCrunch