Anthropic · Released Jun 2, 2026
Claude Fable 5 (with fallback)
Specialized reasoning variant engineered for high-concurrency research pipelines with automated fallback verification protocols.
OpenRating Index
62.3
0–100 composite
Reasoning Index
87.8
0–100 composite
Cost / Task
$3.14
benchmark run
Output speed
72 tok/s
blended tok/s
Time to first token
1.0s
median latency
Input price
$5.5
per 1M tokens
Output price
$28
per 1M tokens
Context window
200K
tokens
Strengths
Fault-tolerant multi-stage verification architecture
Deep mathematical derivation and formal code proving
High fidelity instruction alignment under complex constraints
How we rate Claude Fable 5 (with fallback)
OpenRating scores every model on the same axes. The OpenRating Index is a weighted composite of reasoning, knowledge, and agentic benchmarks, normalised to a 0–100 scale. Speed is blended output measured in tokens per second under standardised load, with time-to-first-token reported separately. Prices are list input and output prices per million tokens, and Task Cost measures end-to-end workload spending.
OpenRating Index
62.3
Reasoning Index
87.8
Token Pricing
Input per 1M tokens
$5.5
Output per 1M tokens
$28
Cost of 1M input + 1M output
$33
Task Cost Economics
Empirical cost breakdown for a standard OpenRating Index benchmark task ($3.14 total).
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Compare Claude Fable 5 (with fallback) with the models it is most often measured against.