Meta has officially released Muse Code (beta), a terminal-based AI coding agent powered by its updated Muse Spark 1.2 model, entering the competitive AI developer tools market alongside OpenAI's Codex and Anthropic's Claude Code. Announced on August 5, 2026, the tool is accessible via Meta's Model API and a simple curl install script, targeting software engineers working on large, complex repositories.
Muse Code is designed to autonomously plan, write, and validate code changes by spawning parallel sub-agents in isolated worktrees, leaving the primary codebase untouched. Meta claims it can handle multi-hour tasks, such as iteratively optimizing GPU kernels over 1,000+ tool calls on Nvidia Hopper GPUs. A standout feature is its replay-exact event log, which records every model call, tool run, and edit, enabling the agent to resume precisely from a crash—a capability Meta highlights as missing from competitors.
In benchmarking, Muse Spark 1.2 trails Anthropic's Opus 5 on all listed coding tests but beats OpenAI's Codex and Google's Antigravity on most. On Terminal-Bench 2.1, Muse Code scored 82.9% versus Opus 5's 86.7%, and on DeepSWE 1.1 it reached 59.3% (vs. 65.0% for Opus 5). Meta's internal benchmarks show similar gaps. However, the agent demonstrated improved efficiency with longer tool-call sequences, which Meta argues matters more for sustained development work.
The release also showcases multimodal capabilities: in one demo, a user feeds a fly-through video of a house, and Muse Code interprets it to generate a functional website with booking features. Additional commands like /plan (approval-gated planning), /grill (stress-testing plans), and /goal (completing objectives) are built in.
Alexandr Wang, Meta's AI chief, told the Wall Street Journal that Muse Code could be an "incredibly good option" from a cost perspective. This move follows Meta's entry into enterprise AI in June with a customer service agent, signaling a broader push beyond advertising. Developers can install the beta via curl -fsSL [script] | bash.
