Claude Fable 5 vs GPT-5.6 Luna
Claude Fable 5 (Anthropic) and GPT-5.6 Luna (OpenAI) compared on benchmarks, pricing, context window, and use-case rankings.
- Claude Fable 5 leads on overall intelligence (ECI 162 vs 156).
- GPT-5.6 Luna is cheaper on input tokens — $0.20 vs $10.00 per 1M.
- GPT-5.6 Luna has a larger context window (1.1M vs 1M tokens).
- Claude Fable 5 ranks higher for coding (98th vs 76th percentile).
| Attribute | Claude Fable 5 | GPT-5.6 Luna |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 162 | 156 |
| Coding | 98 | 76 |
| Math | 97 | 87 |
| Reasoning & Knowledge | 90 | 57 |
| Agentic & Tools | 98 | — |
| Specifications | ||
| Developer | Anthropic | OpenAI |
| Family | Claude | GPT |
| Released | Jun 9, 2026 | Jul 9, 2026 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | 1M | 1.1M |
| Price — $/M input | $10.00 | $0.20 |
| Price — $/M output | $50.00 | $1.20 |
| Inputs | text, image, file | file, image, text |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 100% | 98% |
| APEX | 45% | — |
| ARC-AGI | 99% | 88% |
| ARC-AGI-2 | 89% | 60% |
| GPQA Diamond | 86% | 92% |
| Humanity's Last Exam | 56% | 40% |
| SciCode | 60% | 53% |
| SimpleBench | 82% | 47% |
| SimpleQA Verified | 68% | 42% |
| WebDev Arena | 1654 | 1523 |
| WeirdML | 92% | 61% |
| τ²-bench | 99% | — |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is Claude Fable 5 better than GPT-5.6 Luna?
On Epoch AI's Capabilities Index, Claude Fable 5 scores higher (162) than GPT-5.6 Luna (156). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is cheaper, Claude Fable 5 or GPT-5.6 Luna?
GPT-5.6 Luna is cheaper on input tokens at $0.20 per million, versus $10.00 (representative OpenRouter pricing).
Which has a larger context window, Claude Fable 5 or GPT-5.6 Luna?
GPT-5.6 Luna supports up to 1.1M tokens, compared with 1M for the other.
Which is better for coding, Claude Fable 5 or GPT-5.6 Luna?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Claude Fable 5 ranks higher — 98th vs 76th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.