Claude Opus 5 vs Muse Spark 1.2

Claude Opus 5 and Muse Spark 1.2 are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Opus 5, from Anthropic, has a 1,000,000-token context window, costs from $5.00/1M input and $25.00/1M output tokens across 3 providers and scores 48.1 on the Artificial Analysis Intelligence Index.

Muse Spark 1.2, from Meta, has a 1,048,576-token context window, costs $1.25/1M input and $4.25/1M output tokens and scores 39.6 on the Artificial Analysis Intelligence Index.

Muse Spark 1.2 is the cheapest on input, 4× cheaper than the next model, Muse Spark 1.2 has the largest context window, Claude Opus 5 scores highest for intelligence and Claude Opus 5 leads on coding.