Arena.ai's code model evaluation platform ranking models on WebDev and other tasks by performance and cost.
Anthropic released Claude Fable 5.2 and Claude Mythos 5.2, with Fable 5.2 taking first place on the Code Arena WebDev leaderboard at 1832 points, ahead of Claude Opus 5.5, Gemini 4 Carbon and GPT-6 Astra. Anthropic claims up to 30% faster performance than Fable 5.1 and lower pricing of $8/$40 per million tokens.
Meta's Muse Ember (Max) tops the Code Arena WebDev small-model leaderboard at 1608 points, beating Claude Haiku 5.5 and GPT-6 Luna. At identical API pricing, its median cost per task is just $0.03, roughly half of Luna and a quarter of Haiku, placing it on the cost-performance Pareto frontier. Generations averaged about two minutes each, producing 20+ websites and animations in a single pass.
Meta has introduced Muse Ember, its smallest and most efficient model to date, targeting complex reasoning execution and everyday agent workflows with cross-app operation, sequential tool calling, test running and targeted code fixes, plus a 1M-token context and native multimodal understanding. It tops the Code Arena WebDev small-model ranking at 1608 points, beating Claude Haiku 5.5 and GPT-6 Luna, while sitting on the Pareto frontier at a median cost of just $0.03 per task.