Update: Cursor officially confirms Kimi K2.5 as the chassis, Dark Side of the Moon: made in collaboration with authorized partners

According to 1M AI News monitoring, the official account of the Dark Side of the Moon @Kimi_Moonshot posted a congratulatory message on the release of Composer 2, stating: "Cursor's access to Kimi K2.5 via the Fireworks AI-hosted RL and Inference platform is part of an authorized commercial collaboration."

Following the release of Kimi's official statement, Cursor's co-founder Aman Sanger and VP of Developer Education Lee Robinson publicly confirmed the origin of the framework and disclosed more technical details. Sanger stated that the team evaluated multiple frameworks for perplexity, and Kimi K2.5 "proved to be the strongest," followed by further pretraining and 4x-scale reinforcement learning, deploying through Fireworks AI's inference and RL sampler. Robinson added that approximately 1/4 of the computational power in the final model came from the framework, with the remaining 3/4 from Cursor's own training. Robinson referenced Kimi's official tweet, indicating that the Dark Side of the Moon has confirmed compliance with licensing requirements.

Both Sanger and Robinson acknowledged that the omission of mentioning Kimi's framework in the blog post was "an oversight" and stated that the source of the framework will be promptly noted in the next model release.

Previously, relevant controversies quickly escalated on social media, with Elon Musk also replying to @fynnso's post, "Yeah, it's Kimi 2.5," further fueling the discussion.