xAI has released Composer 2.5, a new model now live inside Grok Build. Announced on June 1, the model is positioned as a fast, highly intelligent option built specifically for long-running tasks and complex instruction-following — the kind of work where most general-purpose models start to lose coherence.
According to xAI, Composer 2.5 is an agentic coding model with particular strengths in coding, agents, JSON, and tool use — including function calling, tool use, and code execution. The model was built on the open-source checkpoint of Moonshot's Kimi K2.5 and trained with 25 times more synthetic tasks than its predecessor, Composer 2. Pricing starts at $0.50 per million input tokens and $2.50 per million output tokens, with a faster variant available at $3.00 and $15.00 per million tokens respectively — reportedly around 100% cheaper on input tokens compared to Grok Build 0.1.
To try it, head to build.grok.com and select Composer from the /models menu. The upgrade is available now — no waitlist mentioned.
Sarah focuses on Tesla Energy, SpaceX missions, and the broader Musk AI portfolio. Former data analyst in clean energy. Based in San Francisco.
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