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Proprietary release

Released September 2026

Claude Fable 5.1: Release Intelligence, Performance & Price

Available providers

The Claude Fable 5.1 release offers 5 models, each with different intelligence, performance, and pricing characteristics. Below is a comparison of the key metrics across the 5 models.

  • For intelligence, the top model of Claude Fable 5.1 is Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback) at 53.
  • For output speed, the fastest model is Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback) at 66 t/s.
  • For latency, Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback) at 8.61s offers the lowest time to first answer token.
  • For pricing, Claude Fable 5.1 (Adaptive Reasoning, Low Effort, Default Fallback) at $2.37 offers the lowest cost per task. Prices vary up to 3.2x across models.

Intelligence

Artificial Analysis Intelligence Index

Artificial Analysis Intelligence Index v4.3.2 incorporates 10 evaluations: AA-Briefcase v1.1, GDPval-AA v2.1, AutomationBench-AA, Terminal-Bench 4.0, SciCode, Humanity's Last Exam, GDP.pdf, CritPt, AA-Omniscience, AA-LCR v1.1

Intelligence Index vs. Cost per Intelligence Index Task

Artificial Analysis Intelligence Index · Weighted average cost (USD) per Artificial Analysis Intelligence Index task
Most attractive quadrant
Claude Fable 5.1
Pareto line

Cost

Cost per Intelligence Index Task

Weighted average cost (USD) per Artificial Analysis Intelligence Index task, segmented by token type. Lower is better

Speed & Latency

Output Speed

Output tokens per second · Higher is better

Capability Scores

Capability Indexes

Measures the performance of models on specific capabilities and industries
Finance & Accounting Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, Humanity's Last Exam, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better

Strategy & Ops Index

Incorporates 6 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, AutomationBench-AA, AA-LCR v1.1, GDP.pdf · Higher is better

Legal Index

Incorporates 7 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, Humanity's Last Exam, AA-LCR v1.1, GDP.pdf, AutomationBench-AA · Higher is better

Healthcare & Medical Index

Incorporates 6 evaluations: AA-Omniscience, GDPval-AA v2.1, AA-Briefcase v1.1, MLCR-AA, Humanity's Last Exam, AutomationBench-AA · Higher is better

Engineering Index

Incorporates 6 evaluations: AA-Omniscience, Humanity's Last Exam, CritPt, GDPval-AA v2.1, AA-Briefcase v1.1, Terminal-Bench 4.0 · Higher is better

Economics Index

Incorporates 5 evaluations: AA-Omniscience, Humanity's Last Exam, GDPval-AA v2.1, AA-Briefcase v1.1, AA-LCR v1.1 · Higher is better

More from Anthropic

Further details

Weights
Provider Benchmarks
Claude Fable 5.1 (Adaptive Reasoning, Max Effort, Default Fallback)
Anthropic logoAnthropic
53
-
1M
$7.2
66
Not available
Anthropic
Claude Fable 5.1 (Adaptive Reasoning, Xhigh Effort, Default Fallback)
Anthropic logoAnthropic
53
-
1M
$7.2
63
Not available
Anthropic
Claude Fable 5.1 (Adaptive Reasoning, High Effort, Default Fallback)
Anthropic logoAnthropic
51
-
1M
$7.2
56
Not available
Anthropic
Claude Fable 5.1 (Adaptive Reasoning, Medium Effort, Default Fallback)
Anthropic logoAnthropic
49
-
1M
$7.2
57
Not available
Anthropic
Claude Fable 5.1 (Adaptive Reasoning, Low Effort, Default Fallback)
Anthropic logoAnthropic
47
-
1M
$7.2
55
Not available
Anthropic