Pairwise benchmark snapshot · Aug 16, 2026
This page compares Claude Fable 5 (Anthropic) and GPT-5.6 Luna (OpenAI) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Claude Fable 5 is ahead by 150 points (1,616 vs 1,466; seed-bootstrap (Aug 16, 2026)). On SWE-bench coding, Claude Fable 5 resolves 80% versus 61.8% (seed-bootstrap (Aug 16, 2026)). GPT-5.6 Luna streams faster (188 tok/s) while GPT-5.6 Luna is the cheaper output token ($0.6/1M). GPT-5.6 Luna has the larger context window (1.1M tokens). Every cell below is a dated snapshot from a named public source — we do not invent missing scores, and we do not run SWE-bench ourselves.
Anthropic
Claude Fable 5Anthropic top-tier long-horizon model. Official API $10/$50 per 1M tokens (Claude Platform pricing, Aug 2026).
OpenAI
GPT-5.6 LunaOpenAI 5.6 fast/cheap tier. Official API $0.20/$1.20 per 1M after the Jul 30 80% Luna cut.
Instant pairwise benchmark recalculation across 400+ LLMs
Category wins across intelligence, speed, and pricing efficiency.
Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy
Generation throughput and time to first token responsiveness
Cost per million tokens and max context window length
Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.
150 pts advantage
130 tok/s faster
$49.40/1M cheaper
Simulate monthly production API costs based on published $/1M tokens.
GPT-5.6 Luna is estimated to save $1,087.50/month ($13,050/year).
Higher SWE-bench (80%).
Lower output list price ($0.6/1M).
Lower TTFT (88 ms).
Larger window (1.1M).
Both accept images. Defaulting to the higher-Elo side (Claude Fable 5).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Fable 5 | Higher SWE-bench (80%). |
| High-volume chat | GPT-5.6 Luna | Lower output list price ($0.6/1M). |
| Voice / low-latency UI | GPT-5.6 Luna | Lower TTFT (88 ms). |
| Long-document RAG | GPT-5.6 Luna | Larger window (1.1M). |
| Screenshots / vision | Claude Fable 5 | Both accept images. Defaulting to the higher-Elo side (Claude Fable 5). |
Luna is the OpenAI fast/cheap 5.6 SKU after Jul 30. It is not Sol. Sort by price and TTFT, not Elo.
Fable 5 is not Sonnet with extra adjectives. It is the expensive long-horizon row. Read SWE-bench and output price together.
High-volume agents that cannot pay Sol. Compare to Luna before you assume the new cheap SKU wins.
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The real PNG is generated at /compare/claude-fable-5-vs-gpt-5-6-luna/opengraph-image for crawlers.
Verified head-to-head card
