Muse Code is Meta’s command-line coding agent, and since 12 October 2026 it is the main way to use Meta’s most capable model, Muse Wonder Full. This guide explains how to install Muse Code on Mac, Linux or Windows, sign in, choose between Muse Wonder and Muse Spark, set safe permissions and pick a subscription, as well as one setting every new user should check: Contributor mode, which lets Meta train on your code and is switched on by default for subscribers.