According to 1M AI News monitoring, the official account of Moonshot, @Kimi_Moonshot, posted congratulations on the launch of Composer 2 and stated: "Cursor accesses Kimi K2.5 via Fireworks AI's hosted RL and inference platform under authorized commercial collaboration."

Following the official statement from Kimi, Cursor co-founder Aman Sanger and Vice President of Developer Education Lee Robinson publicly confirmed the model foundation and disclosed additional technical details. Sanger noted that the team conducted perplexity evaluations across multiple base models, concluding that Kimi K2.5 "proved to be the strongest." The model was subsequently enhanced with continued pre-training and fourfold-scale high-compute reinforcement learning, deployed through Fireworks AI’s inference and RL sampling pipeline. Robinson added that approximately one-quarter of the final model’s compute originated from the base model, while the remaining three-quarters came from Cursor’s own training. Robinson cited Kimi’s official tweet, affirming that Moonshot has confirmed compliance with licensing requirements.

Sanger and Robinson both acknowledged that omitting mention of the Kimi base model in the initial blog post was "a mistake," stating that future model releases will immediately disclose the foundational source.

Previous controversies rapidly gained traction on social media, with Elon Musk replying under @fynnso’s post, “Yeah, it's Kimi 2.5,” further amplifying the topic’s visibility.