PyyanThe AI Index

Pyyan / Compare / Claude Fable 5 vs Claude Sonnet 5

Claude Fable 5 vs Claude Sonnet 5

2 of 5

Language Models · verified 13 Aug 2026

Claude Fable 5Anthropiccurrent
Claude Sonnet 5Anthropiccurrent
3 slots left
SpecificationClaude Fable 5Claude Sonnet 5
SummaryMost capable widely released model, for the hardest reasoning and long-horizon agentic work.Near-Opus quality on coding and agentic work at Sonnet cost.
Context1M1M
Input ($/Mtok)$10$3
Output ($/Mtok)$50$15
LicenceProprietaryProprietary
Max output128K128K
Model IDclaude-fable-5claude-sonnet-5
CategoryLanguage ModelsLanguage Models
OfficialAnthropic ↗Anthropic ↗

Highlighted rows are where these differ.

Claude Fable 5

  • Thinking is always on — the `thinking` param is rejected
  • Raw chain of thought is never returned
  • Requires 30-day data retention; unavailable under ZDR

Best for the hardest problems.

Full spec sheet →

Claude Sonnet 5

  • Adaptive thinking on by default
  • New tokenizer — roughly 30% more tokens for the same text
  • Introductory $2/$10 through 31 Aug 2026

Best for high-volume production.

Full spec sheet →