GPT-5.1-Codex vs Muse Spark Open

GPT-5.1-Codex against Muse Spark Open
GPT-5.1-CodexMuse Spark Open
Coding index15.347.4
Benchmarks behind it Partial, 2 benchmarks Verified, 4 benchmarks
Output $/Mtok$10.00$4.25
Cost per solved task$0.892Not computable
Context window400K1.05M