Summary
Jack Roberts puts Claude Opus 5.5 head to head with OpenAI’s GPT-6 Astra to see which delivers more in practice. He opens with the headline claims that Opus 5.5 is about 40% cheaper and 30% faster than Fable, and briefly covers the newly released Sol and Luna models, which are positioned as far cheaper than Astra but not frontier-class.
The comparison runs across several real tasks using identical one-shot prompts: rebuilding a personal website from a deliberately poor starting point, producing a launch film, creating animations, building a game and developing branding. Video and image assets are generated through Higgsfield’s newly launched API. On the website test Roberts prefers Opus 5.5’s graphics and animation, though he notes the copy still feels somewhat AI-written and recommends specifying typography in the prompt.
The launch film is close to a tie. The standout is a JavaScript animation for his speech-tech startup Glido, where Opus 5.5 produces detailed, on-brand animation with sound and no generated images, which he calls a clear win. The video is useful for anyone deciding between the two flagship models for design and front-end work.
📺 Source: Jack Roberts · Published September 23, 2026
🏷️ Format: Comparison
