Muse Code

Muse Code is a terminal-based coding agent developed by Meta, designed for complex software-engineering tasks carried out at whole-repository scale. It was announced on August 5, 2026 (by Mark Zuckerberg) and released in beta for macOS and Linux; installation is done with a single terminal command (curl -fsSL https://dev.meta.ai/install.sh | bash). Muse Code is powered by the Muse Spark 1.2 model and positioned as a competitor to Claude Code (Anthropic) and Codex (OpenAI).

Muse Code's key features are: asynchronous background agents (specialized agents remain active throughout each session rather than being spawned per task), repository-scale execution (planning changes, writing code and validating results across large codebases), and persistence based on a local event log in which every model call, tool run, approval and edit is appended - enabling crash recovery and long-running tasks.

Muse Code offers built-in skills invoked by commands, including /plan (approval-gated planning), /grill (stress-testing solutions) and /goal (task completion). The Muse Spark 1.2 model that powers it is a coding-focused update - with significantly scaled-up training compute on coding tasks, co-trained with Muse Code and trained on long-horizon tasks including whole-repository generation. Muse Code is available in beta and via the Meta Model API.