Meta Releases Muse Code and Muse Spark 1.2 for Long-Sequence Agentic Coding

Simon Willison · rss · 2026-08-06

Meta released Muse Spark 1.2, a coding-focused model, alongside the Muse Code agent. Muse Spark 1.2 features significant improvements in code generation, complex debugging, and end-to-end developer workflows.

This update highlights the growing importance of long-sequence agentic tool calling. Meta scaled up training compute on coding tasks, expanded environment diversity, and co-trained the model using rejection sampling and subagent optimizations. The model excels at long-horizon coding tasks like whole-repository generation and large projects.

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