Muse Spark 1.2 is Meta's reasoning model for complex agentic tasks, accepting text, images, video, audio, and PDF documents and returning text, with a 1,048,576-token context window. Called via the Responses API, it supports cross-turn reasoning replay, tool-calling loops, built-in web search grounding, and file inputs, with configurable reasoning effort and structured JSON output. Meta reports strong results on multi-file refactors, extended debugging sessions, and whole-repository generation.
meta/muse-spark-1.2Aug 22, 2025+1