Software development is entering a new era where artificial intelligence is no longer limited to suggesting individual lines of code. Developers can now give AI systems larger engineering tasks and allow them to inspect repositories, plan changes, write code, run tools, and validate their work. Muse Code is one of the newest tools entering this rapidly evolving space. Released by Meta in beta in August 2026, Muse Code is a terminal-based AI coding agent powered by Muse Spark 1.2. Meta designed it to handle complex software-engineering tasks across large repositories, including planning changes, writing code, and validating results. (Meta AI Research) What makes Muse Code particularly interesting is its use of persistent background agents that can continue working on parts of a task while the main agent coordinates the overall process. (Meta AI Research) In this guide, we'll explore what Muse Code is, how it works, its key features, use cases, limitations, pricing consi...