Claude Opus 5.5 Beats GPT-6 Astra on Creative Tasks, Costs 60% Less

Anthropic's Claude Opus 5.5 outperformed OpenAI's flagship GPT-6 Astra on creative design work while costing significantly less, according to side-by-side evaluations released in late September 2026. When both models were given identical prompts to generate a "jelly koi pond"—a test of creative interpretation and output quality—Opus 5.5 produced a fully realized gummy aquarium for $12.38, while Astra's output exhibited unexpected behavior including what users describe as physics glitches that rendered the task result unstable.