Claude Fable 5 (Max, Opus 4.8 Fallback) vs GPT-6 Luna (Medium)
Which is better for the money: Claude Fable 5 (Max, Opus 4.8 Fallback) by Anthropic or GPT-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 (Max, Opus 4.8 Fallback) scores 19.7 points higher (49.6 vs 29.9) but costs 358× as much to run the benchmark ($11161 vs $31.2; flagship vs budget cost classes). They are not alternatives at one budget: pick Claude Fable 5 (Max, Opus 4.8 Fallback) when you need intelligence above 29.9, and GPT-6 Luna (Medium) when 29.9 is enough.
| Metric | Claude Fable 5 (Max, Opus 4.8 Fallback) | GPT-6 Luna (Medium) | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 49.6 | 29.9 | −39.7% GPT-6 Luna (Medium) is 39.7% less intelligent |
| Total AA cost (lower is better) | $11,160.86 | $31.17 | −99.7% GPT-6 Luna (Medium) is 99.7% cheaper |
| End-to-end time (lower is better) | 85.47s | Not reported | — not comparable |
| Price per 1M tokens (in / out) | $10.0 / $50.0 | $0.10 / $0.50 | |
| Input modalities | Text, Image | Text, Image |
GPT-6 Luna (Medium) vs Claude Fable 5 (Max, Opus 4.8 Fallback): 39.7% less intelligence, 99.7% less cost to run the AA benchmark, and end-to-end time not fully reported.
Against the frontier
- Claude Fable 5 (Max, Opus 4.8 Fallback) is off the frontier: at the same or lower cost, Claude Opus 5.5 (Max, Default Fallback) scores 57.60 for $8708.
- GPT-6 Luna (Medium) is on today's frontier: nothing is both smarter and cheaper.
Compare something else
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/claude-fable-5/gpt-6-luna-medium · Markdown: /api/v1/compare/claude-fable-5/gpt-6-luna-medium?format=md · llms.txt · agent skill