Claude Fable 5.1 (Max, Default Fallback) vs GPT-5.6 Luna (Medium)
Which is better for the money: Claude Fable 5.1 (Max, Default Fallback) by Anthropic or GPT-5.6 Luna (Medium) by OpenAI? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-26.
Depends on your budget
Claude Fable 5.1 (Max, Default Fallback) scores 28.4 points higher (53.4 vs 25.0) but costs 296× as much to run the benchmark ($13129 vs $44.3; flagship vs budget cost classes). They are not alternatives at one budget: pick Claude Fable 5.1 (Max, Default Fallback) when you need intelligence above 25.0, and GPT-5.6 Luna (Medium) when 25.0 is enough.
| Metric | Claude Fable 5.1 (Max, Default Fallback) | GPT-5.6 Luna (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 53.4 | 25.0 | −53.2% GPT-5.6 Luna (Medium) is 53.2% less intelligent |
| Total AA cost (lower is better) | $13,128.86 | $44.32 | −99.7% GPT-5.6 Luna (Medium) is 99.7% cheaper |
| End-to-end time (lower is better) | 224.26s | 6.50s | −97.1% GPT-5.6 Luna (Medium) is 97.1% faster |
| Price per 1M tokens (in / out) | $10.0 / $50.0 | $0.20 / $1.20 | |
| Input modalities | Text, Image | Text, Image |
GPT-5.6 Luna (Medium) vs Claude Fable 5.1 (Max, Default Fallback): 53.2% less intelligence, 99.7% less cost to run the AA benchmark, and 97.1% faster end-to-end.
Against the frontier
- Claude Fable 5.1 (Max, Default Fallback) is off the frontier: at the same or lower cost, Claude Opus 5.5 (Max, Default Fallback) scores 57.60 for $8708.
- GPT-5.6 Luna (Medium) is off the frontier: at the same or lower cost, GPT-6 Luna (Medium) scores 29.90 for $31.2.
Compare something else
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/claude-fable-5-1/gpt-5-6-luna-medium · Markdown: /api/v1/compare/claude-fable-5-1/gpt-5-6-luna-medium?format=md · llms.txt · agent skill