Claude Fable 5.1 vs GPT-5.6 Luna: Specs & Benchmark Comparison
| Characteristic | Claude Fable 5.1 | GPT-5.6 Luna |
|---|---|---|
| Company | Anthropic | OpenAI |
| Release Date | September 1, 2026 | July 9, 2026 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 1.0M | 1.1M |
| Context (output) | 128K | 128K |
| Input Price / 1M | $10.00 | $0.20 |
| Output Price / 1M | $50.00 | $1.20 |
| Average Score | 0.6 | 0.5 |
| Benchmarks | ||
| OSWorld 2.0 | 0.8 | 0.5 |
| AutomationBench | 0.3 | 0.1 |
Visual Benchmark Comparison
Claude Fable 5.1
GPT-5.6 Luna
OSWorld 2.00.8 vs 0.5
0.8
0.5
AutomationBench0.3 vs 0.1
0.3
0.1
Verdict
GPT-5.6 Luna leads in 2 out of 4 comparison categories.
Overall Performance
Both models show comparable average scores: Claude Fable 5.1 — 0.6, GPT-5.6 Luna — 0.5.
API Cost
GPT-5.6 Luna is 42.9x cheaper: input $0.20/1M vs $10.00/1M tokens.
Context Window
GPT-5.6 Luna supports a larger context: 1M vs 1M tokens.
Recency
Claude Fable 5.1 is newer: released 9/1/2026 vs 7/9/2026.
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Frequently Asked Questions
Which is better for coding — Claude Fable 5.1 or GPT-5.6 Luna?
Direct comparison on the SWE-Bench benchmark is not available. We recommend reviewing other metrics on the comparison page.
Which model is cheaper — Claude Fable 5.1 or GPT-5.6 Luna?
GPT-5.6 Luna is cheaper for input: $0.20 per 1M tokens vs $10.00.
Which has a larger context window — Claude Fable 5.1 or GPT-5.6 Luna?
GPT-5.6 Luna supports a larger context: 1,050,000 tokens vs 1,048,576.
The Claude Fable 5.1 and GPT-5.6 Luna comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Claude Fable 5.1 or GPT-5.6 Luna page. See also the complete list of AI model comparisons.