Muse Code (Beta) and Muse Spark 1.2

A terminal coding agent for long-horizon software engineering, plus the Muse Spark 1.2 model co-trained with it, for developers on macOS and Linux.

Muse Code plans changes, writes code, and validates results across large multi-file repositories from the terminal
A simple primary agent loop is paired with persistent async background sub-agents that stay alive for the whole session, so they avoid re-gathering context and need less steering on hard tasks
Every model call, tool run, approval, and edit is appended to a local append-only event log, which Meta describes as replay-exact and restart-safe for crash recovery and exact session replay
Ships with three skills: /plan for approval-gated planning, /grill for stress-testing, and /goal for objective completion
Muse Spark 1.2 was co-trained with the agent using a self-improvement loop in which Muse Spark 1.1 generated training data, with scaled-up coding-task compute and environment diversity
Installs on macOS and Linux via curl -fsSL https://dev.meta.ai/install.sh | bash; the model is also on the Meta Model API at $1.25 per million input tokens and $4.25 per million output

Multi-file repository work where the agent has to plan, edit, and validate across a long session

A coding task spans many files and steps and you want an auditable record of everything the agent did

Engineers running agentic coding in the terminal who need crash recovery and exact session replay

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