Muse Spark Open (Meta)

About Muse Spark Open

Muse Spark Open is a coding-optimized open-weight model from Meta. It was trained specifically for agentic coding workflows, and Meta says it delivers higher first-attempt accuracy, reliable tool calling, and deep codebase understanding. It became available in October 2026, which makes it one of the newest models in free-pi.

The model accepts text, image, video, file, and audio input and produces text. Its context window is about one million tokens and a response can be up to about 940,000 tokens. It supports reasoning with an effort setting, tool calling, and structured outputs. With tool calling, the free-pi agent can read and edit files, run commands, and use free-pi's built-in web search and documentation lookup tools.

On Design Arena it ranks 10th in the website category.

In free-pi it is free to use with no API key and no card, but it is a premium model. It counts as about 0.04x usage, which means it uses your daily allowance quickly.

When to pick it

For agentic coding with an open-weight model built for that purpose, and for tasks that include audio, video, or screen captures, pick Muse Spark Open. Expect it to use your allowance quickly.

For other premium models with published Intelligence Index scores, pick Claude Sonnet 5.5, GPT-6.1 Sol, or Gemini 4 Argon. For work that should last the day, pick the default DeepSeek V4 Flash.