According to 1M AI News monitoring, Moonshot AI's official account @Kimi_Moonshot posted congratulations on the release of Composer 2, clarifying: "Cursor accesses Kimi K2.5 through Fireworks AI's hosted RL and inference platform, which is an authorized commercial partnership." Following Kimi's official statement, Cursor co-founder Aman Sanger and Vice President of Developer Education Lee Robinson publicly confirmed the source of the base model and disclosed more technical details. Sanger stated that the team evaluated multiple base models for perplexity, and Kimi K2.5 "proved to be the strongest." This was followed by continued pre-training and 4x scale high-compute reinforcement learning, deployed through Fireworks AI's inference and RL sampler. Robinson added that the compute from the base model accounts for approximately 1/4 of the final model, with the remaining 3/4 coming from Cursor's own training. Robinson cited Kimi's official tweet, stating that Moonshot AI has confirmed its use complies with licensing requirements. Both Sanger and Robinson admitted that failing to mention the Kimi base model in their release blog was "an oversight" and pledged to clearly state the base model source in their next model release. Previously, related controversies quickly escalated on social media, with Elon Musk also replying to @fynnso's post with "Yeah, it's Kimi 2.5," further amplifying the topic's heat.