Release2026-09-02

Meta released Muse Spark 1.3, its latest model for agent and coding work. It is available today in Muse Code and the Meta Model API. Earlier reasoning modes ship now. A new max reasoning mode follows once safety testing finishes. Meta says the model sustains longer tasks and tracks work across a single long thread. It asks clarifying questions, requests help when stuck, and confirms before consequential actions. Meta engineers measured fewer tool calls and fewer tokens than version 1.2 on coding tasks. Meta also reports stronger resistance to prompt injection and better judgement on irreversible actions. Meta says bigger models and an open weights release of Muse Spark are planned.

What changed

Muse Spark 1.2 used more turns, more tokens and was more verbose in coding work.

What it unlocks

Running longer multi-step agent tasks that ask clarifying questions before acting.

  • ~20% fewer tool calls
  • ~25% fewer tokens

What you need to act on it

  • access to Muse Code or the Meta Model API

Send this to someone who needs it

Shares the story and its sources. Nothing about you.

What does this mean for your job?

This is the story as everyone gets it. Once a week we send you the version written for your role — what changed, why it matters for the work you actually do, and one thing to try. Free while we tune it.