Claude Fable 5.1

Best for

Senior teams shipping production frontends who want the strongest all-round model and will pay for it

Price & access

$10 in / $50 out per 1M; cache read $0.25 (75% cheaper than Fable 5), cache write $12.50; Anthropic reports ~25% lower typical workload cost and up to ~45% savings on complex agentic coding vs Fable 5

Evidence summary

First-party launch post, Bedrock card, Anthropic pricing page, plus two independent human-preference boards and a third-party SWE-bench Pro leaderboard all place it at or near the top.

Edition status

No prior snapshot. Tracked in the September 2026 baseline.

Strengths

• SWE-bench Pro rank 1 (81.2%) and AA Intelligence Index rank 1 (57)
• Arena WebDev Frontend rank 2 (1796) plus Design Arena Website rank 3 (1330) - strong on both human-preference boards
• Best-documented debugging evidence (Red Hat diagnosed every broken build; Millennium's one-in-a-million crash)
• Cache reads at $0.25 cut agentic loop costs sharply

Tradeoffs

• $10/$50 top-tier pricing
• AA measured TTFT of 266.51 s at max effort
• Anthropic's own table shows Fable 5 ahead on Terminal-Bench 4.0 in the Mythos row - effort settings matter
• Arena row has only 1,893 votes