Claude Fable 5 vs GPT-5.6 Luna
Detailed comparison of API pricing, technical specifications, and benchmark scores. Updated 2026-06-29.
Cost at a Glance
Claude Fable 5 is 8.8× more expensive than GPT-5.6 Luna — switching could save 88.7% on your monthly API bill.
At 5M input + 2M output tokens per month:
Choosing GPT-5.6 Luna could save you $133.00/mo
Price Comparison (per 1M tokens)
| Metric | Claude Fable 5 | GPT-5.6 Luna |
|---|---|---|
| Input (per 1M tokens) | $10.00 | $1.00 |
| Output (per 1M tokens) | $50.00 | $6.00 |
| Cache Write (per 1M tokens) | $12.50 | $1.25 |
| Cache Read (per 1M tokens) | $1.00 | $0.10 |
| Batch Input (per 1M tokens) | $5.00 | $0.50 |
| Batch Output (per 1M tokens) | $25.00 | $3.00 |
Prices are per 1 million tokens. Actual costs depend on your monthly token volume. Use the calculator →
Specifications
| Spec | Claude Fable 5 | GPT-5.6 Luna |
|---|---|---|
| Context Window | 1M | 1M |
| Max Output Tokens | 128K | 64K |
| Knowledge Cutoff | 2026-04 | 2026-04 |
| Modalities | Text, Image | Text |
| Prompt Caching | Yes | Yes |
| Batch API | Yes | Yes |
| Thinking / Reasoning | Yes | No |
Benchmark Scores
| Benchmark | Claude Fable 5 | GPT-5.6 Luna |
|---|---|---|
| SWE-bench Verified | 88.7 | 62.5 |
| MMLU-Pro | 88.5 | 79.0 |
| HumanEval | 96.3 | 89.5 |
Benchmark scores from official provider reports. Higher is better. Missing scores indicate the provider has not published that benchmark yet.
Use Cases
Claude Fable 5
GPT-5.6 Luna
About the Providers
Claude Fable 5 is developed by Anthropic. GPT-5.6 Luna is developed by OpenAI. This is a cross-provider comparison between Anthropic and OpenAI models. For the most up-to-date pricing, always check the official API documentation from each provider.