Meta just shipped two things at once: Muse Spark 1.2, the model, and Muse Code, an agentic harness that wraps around it. The interesting part is that they pull in opposite directions. On raw coding the model is a clear underdog. As an agent it is suddenly near the top. Here is what actually held up when I tested it.
Prefer the quick version? I covered the benchmark split, the broken games, the harness features, and a head to head against Qwen 3.8 in this video:
What Muse Spark and Muse Code are
Muse Spark 1.2 is Meta's new coding model. Muse Code is the harness you actually run it in. The harness keeps a local log of every tool call and every edit, so if a run crashes it picks up exactly where it left off instead of starting over. It ships with built-in skills too: /plan turns a task into an approval-gated plan, /grill stress-tests that plan before you run it, and /goal keeps the agent pushing toward the objective.
Where it loses
On the coding benchmarks it never comes first
Discussion
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