Cursor acknowledges its new low-cost coding model has Chinese bones

Cursor has recently acknowledged that its latest coding model, Composer 2, has connections to Chinese technology, a fact that was initially overlooked in their earlier presentations. Over the weekend, Cursor's leadership took to X to clarify that Composer 2 was built upon Kimi K2.5, an open-source model developed by the Chinese startup Moonshot AI. Aman Sanger, co-founder of Cursor, expressed that Kimi K2.5 emerged as the most robust option after evaluating various base models based on perplexity metrics. "It was a miss to not mention the Kimi base in our blog from the start," he noted in his posts. This revelation was prompted by an X user, Fynn, who claimed that Composer 2 was essentially Kimi 2.5 enhanced with additional reinforcement learning techniques. Fynn's assertion was backed by code snippets that hinted at Kimi's foundational role. In response, Cursor's vice president of developer education, Lee Robinson, confirmed the use of Kimi K2.5 as the open-source foundation for Composer 2. He assured that future iterations would undergo comprehensive pretraining and clarified that only about a quarter of the computational resources allocated to the final product were derived from the Kimi base, with the majority coming from their own training efforts. Robinson also highlighted that Cursor is adhering to the licensing agreements associated with Kimi through its inference provider. In a post on X, Moonshot AI announced that Cursor is utilizing Kimi K2.5 under a legitimate commercial partnership, expressing their support for the integration of their model into Cursor’s framework. Cursor, valued at $29.3 billion as of November, recently touted Composer 2 as a groundbreaking tool for coding, pricing it competitively at $0.50 per million input tokens and $2.50 per million output tokens. This pricing structure positions Composer 2 as significantly more affordable than offerings from competitors like Anthropic, whose Claude Opus 4.6 charges $5 per million input tokens and $25 per million output tokens. The news has sparked a lively discussion on X, with many users expressing surprise at Kimi’s performance following the revelation that Composer 2 is built on that model. Some users noted the impressive coding benchmarks achieved by Kimi compared to more established models, while others criticized Cursor for not disclosing Kimi's role earlier, suggesting that the company is merely a layer for routing models instead of a true integrated development environment (IDE).