Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback) vs Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)

Anthropic · Anthropic · catalog 2026-09-14

Trade-off: Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback) is cheaper ($7.175 vs $7.7/M); Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) scores higher on intelligence (49.7 vs 49.1).
Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback)Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback)
Speed (tok/s)49.6 measured66.8 measured
Blended $/M$7.175 derived$7.7 derived
Intelligence index49.1 measured49.7 measured
TTFT (ms)594 measured8141 measured
Context—1000k list
Coding index77 measured77 measured
Agentic index51 measured51 measured

Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback) card · Claude Fable 5 (Adaptive Reasoning, Max Effort, Opus 4.8 Fallback) card · 3D observatory

Verdicts use price×intelligence dominance only, and only where both sides are measured; null cells stay null with their provenance (em-dash = not in catalog). Percentile-free by design — this page compares two models, not the field. Generated page — do not hand-edit.