Anthropic · Language model

Claude Fable 5.1

Anthropic's largest publicly available model. Fable 5.1 is priced at the premium tier and leads the Arena agent leaderboard.

MakerAnthropic
ReleasedSeptember 1, 2026
API price (per 1M tokens)$10 in / $50 out
Open weightsNo

Best for

  • The hardest reasoning problems
  • Long-running agents
  • High-stakes research

Strengths

  • #1 on the Arena agent leaderboard
  • Cache reads cut to $0.25 per million tokens

Watch out for

  • Premium price: 2.5x Opus 5.5
  • Shipped with breaking API changes

Ranking history

EditionPower RankingsCodingBest ValueOpen-Weight WatchImage GenerationVideo Generation
Week 39, 2026#2 (95)#3 (93)————

Head-to-head