Muse Spark 1.3 scores 64 on coding agent index at a fifth of Opus 5's cost

Meta's Muse Spark 1.3 (max), which is in limited preview for Meta's partners, scores 68 on the Artificial Analysis Coding Agent Index in the Muse Code harness, #2 behind only Claude Opus 5 (xhigh) in Claude Code. The variant available now, Muse Spark 1.3 (xhigh), scores 64 and costs the least per task of any agent above a 60 index score Muse Spark 1.3 (xhigh) enters the Artificial Analysis Coding Agent Index at 64 in Muse Code, up 2 points from Muse Spark 1.2 (62, August). It enters level with Grok 4.5 (high) in Grok Build (64) and behind GPT-5.6 Sol (max) in Codex (65). At $1.72 per task, it costs the least of any agent above a 60 index score, around a fifth of the cost of Claude Opus 5 (xhigh) in Claude Code ($8.17) Muse Spark 1.3 (max), which is in a limited preview stage, lands at 68 in Muse Code. It enters behind only Claude Opus 5 (xhigh) in Claude Code (68), and ahead of Claude Fable 5 (max) in Claude Code (67) and GPT-5.6 Sol (max) in Codex (65). Muse Spark 1.3 (max) is excluded from cost comparisons as Meta has not announced pricing for the limited release Claude Fable 5.1 results are in progress and will be added when complete. Congratulations @AIatMeta, @finkd, and…