Meta's Muse Code AI coding agent

Meta has released Muse Code, its first public AI coding agent, powered by Muse Spark 1.2, with expanded global access through the Meta Model API at $1.25 per million input tokens and $4.25 per million output tokens. On Text Arena, Muse Spark 1.2 (xHigh) scored 1498 points, placing it #4 and trailing top-ranked Claude Fable 5 (1507 points) by nine points while costing roughly 91% less at scale. On the Artificial Analysis Intelligence Index for agentic performance, Muse Spark 1.2 tied with Grok 4.5. Muse Code features a one-million-token context window, parallel subagents, replayable history, a persistent goal system, and explicit operating modes including planning, code critique, documentation-grounded review, and interface evaluation. Meta is directing engineers to use Muse Code internally to reduce dependence on external coding tools and to help post-train a future model. The prior version, Muse Spark 1.1, launched July 16 and was limited to the US.