Cursor Faces Scrutiny Over Composer 2’s Chinese Open-Source Foundations

New updates have been reported about Cursor.

Cursor is under scrutiny after users on X alleged its new Composer 2 coding model is largely based on Kimi 2.5, an open-source model from China’s Moonshot AI, raising questions about transparency in the company’s flagship AI product. The issue gained attention because Cursor, a U.S. startup reportedly valued at $29.3 billion and generating more than $2 billion in annualized revenue, initially did not disclose any reliance on Kimi in its launch communications.

In response, Cursor executive Lee Robinson confirmed that Composer 2 was built on an open-source base but emphasized that roughly three-quarters of the compute for the final model came from Cursor’s own training, which he said materially differentiates its performance from Kimi. Both Cursor and Kimi stated that the use of Kimi 2.5 complies with licensing terms and occurs via an authorized commercial partnership with Fireworks AI, while co-founder Aman Sanger conceded it was a mistake not to credit Kimi from the outset and pledged clearer disclosure for future versions, amid heightened U.S.–China sensitivities in the AI race and investor focus on proprietary technology and IP risk.