Anthropic will hold the top slot on the arena.ai Code Arena WebDev Leaderboard on October 31, 2026, denying Meta the lead and protecting its benchmark advantage. As of August 12, 2026 Anthropic’s claude-opus-5-max was ranked #1 with a score of 1679 while Meta’s muse-spark-1.1 and muse-spark-1.2 wer…