Claude Fable 5.1 vs GPT-5.6 Luna: Release Comparison
Comparison of the Claude Fable 5.1 and GPT-5.6 Luna releases: 5 and 6 models respectively, each with different intelligence, performance, and pricing characteristics. Below is a comparison of the key metrics across all 11 models.
- For intelligence, Claude Fable 5.1 scores highest: Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback) at 53, against GPT-5.6 Luna (max) at 38 for GPT-5.6 Luna.
- For output speed, GPT-5.6 Luna is fastest: GPT-5.6 Luna (xhigh) at 117 t/s, against Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback) at 66 t/s for Claude Fable 5.1.
- For cost per task, GPT-5.6 Luna is cheapest: GPT-5.6 Luna (low) at $0.01, against Claude Fable 5.1 (Adaptive Reasoning, Low Effort, Default Fallback) at $2.37 for Claude Fable 5.1.
Releases compared
Intelligence
Artificial Analysis Intelligence Index
Intelligence Index vs. Cost per Intelligence Index Task
Cost
Cost per Intelligence Index Task
Speed & Latency
Output Speed
Capability Scores
Capability Indices
Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2, AA-Briefcase, Humanity's Last Exam, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better
Incorporates 6 evaluations: AA-Omniscience, GDPval-AA v2, AA-Briefcase, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better
Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2, AA-Briefcase, Humanity's Last Exam, AA-LCR v1.1, GDP.pdf, AutomationBench-AA · Higher is better
Incorporates 6 evaluations: AA-Omniscience, GDPval-AA v2, AA-Briefcase, MLCR-AA, Humanity's Last Exam, AutomationBench-AA · Higher is better
Incorporates 6 evaluations: AA-Omniscience, Humanity's Last Exam, CritPt, GDPval-AA v2, AA-Briefcase, Terminal-Bench 4.0 · Higher is better
Incorporates 5 evaluations: AA-Omniscience, Humanity's Last Exam, GDPval-AA v2, AA-Briefcase, AA-LCR v1.1 · Higher is better
Further details
Input modality | Output modality | Weights | Provider Benchmarks | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback) |  Anthropic | 53 | 57 | 60 | 61 | 58 | 57 | 63 | $7.63 | $7.2 | $10.00 | $50.00 | $0.25 | $13,129 | 78k | 47k | 188M | 66 | 234.98s | 234.98s | 242.56s | 755.04s | - | 1M | Sep 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| Claude Fable 5.1 (Adaptive Reasoning, Xhigh Effort, Default Fallback) | Anthropic | 53 | 56 | 58 | 61 | - | 57 | 62 | $5.98 | $7.2 | $10.00 | $50.00 | $0.25 | $9,063 | 61k | 34k | 121M | 58 | 85.53s | 85.53s | 94.12s | 677.63s | - | 1M | Sep 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| Claude Fable 5.1 (Adaptive Reasoning, High Effort, Default Fallback) | Anthropic | 51 | 54 | 56 | 58 | - | 55 | 60 | $3.91 | $7.2 | $10.00 | $50.00 | $0.25 | $5,242 | 38k | 19k | 62M | 51 | 12.45s | 12.45s | 22.32s | 469.10s | - | 1M | Sep 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback) | Anthropic | 49 | 52 | 54 | 57 | - | 52 | 58 | $2.98 | $7.2 | $10.00 | $50.00 | $0.25 | $3,983 | 28k | 12k | 44M | 51 | 7.47s | 7.47s | 17.31s | 333.43s | - | 1M | Sep 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| Claude Fable 5.1 (Adaptive Reasoning, Low Effort, Default Fallback) | Anthropic | 47 | 49 | 52 | 54 | - | 49 | 55 | $2.37 | $7.2 | $10.00 | $50.00 | $0.25 | $3,158 | 22k | 8k | 33M | 50 | 5.13s | 5.13s | 15.04s | 280.39s | - | 1M | Sep 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| GPT-5.6 Luna (max) |  OpenAI | 38 | - | - | - | - | 36 | 43 | $0.18 | $0.2 | $0.20 | $1.20 | $0.02 | $320 | 41k | 28k | 154M | 115 | 124.21s | 124.21s | 128.56s | 364.90s | - | 1M | Jul 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - |  | |
| GPT-5.6 Luna (xhigh) | OpenAI | 35 | 38 | 41 | 35 | 33 | 34 | 41 | $0.09 | $0.2 | $0.20 | $1.20 | $0.02 | $179 | 24k | 15k | 85M | 117 | 45.03s | 45.03s | 49.32s | 201.94s | - | 1M | Jul 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - |  | |
| GPT-5.6 Luna (high) | OpenAI | 32 | 35 | 37 | 33 | 30 | 32 | 38 | $0.04 | $0.2 | $0.20 | $1.20 | $0.02 | $108 | 14k | 7k | 50M | 109 | 8.74s | 8.74s | 13.31s | 133.23s | - | 1M | Jul 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| GPT-5.6 Luna (medium) | OpenAI | 25 | 27 | 29 | 28 | 25 | 27 | 32 | $0.02 | $0.2 | $0.20 | $1.20 | $0.02 | $44 | 4k | 2k | 18M | 112 | 2.36s | 2.36s | 6.81s | 39.50s | - | 1M | Jul 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| GPT-5.6 Luna (low) | OpenAI | 22 | 24 | 23 | 25 | 21 | 23 | 29 | $0.01 | $0.2 | $0.20 | $1.20 | $0.02 | $27 | 3k | 559 | 10M | 98 | 2.19s | 2.19s | 7.26s | 24.92s | - | 1M | Jul 2026 | - | Yes | Supports: text and image | Supports: text | Not available | - | | |
| GPT-5.6 Luna (Non-reasoning) | OpenAI | 16 | 17 | 15 | 18 | - | 19 | 22 | $0.01 | $0.2 | $0.20 | $1.20 | $0.02 | $23 | 2k | 0 | 5M | 107 | 0.85s | 0.85s | 5.53s | 18.94s | - | 1M | Jul 2026 | - | No | Supports: text and image | Supports: text | Not available | - | | |