Claude Fable 5.1

• Joint first on the re-based Artificial Analysis Intelligence Index v4.3 (53, level with GPT-6 Astra), first on the official Terminal-Bench v4.0 board at 57.9%, and first on Vellum's quality/speed/cost composite at 65%.
• On Arena text it sits at 1504 inside a 1-6 tie band with the rest of the Anthropic top group.
• Costs more per Index task than GPT-6 Astra ($7.63 against $3.26), so price the alternative if volume matters.

• artificialanalysis.ai/models
• lmarena.ai/leaderboard
• www.vellum.ai/llm-leaderboard
• www.tbench.ai/leaderboard
• www.anthropic.com/claude/fable
• openai.com/index/gpt-6-astra
• x.com/kimmonismus/status/2095824384753549517
• x.com/kimmonismus/status/2095778910998855703

Vendor numbers are treated as claims until independently reproduced — how we judge. Structured benchmark comparisons are on the roadmap.

• The Arena text board is tight at the top: on the 2 September snapshot Fable 5 leads at 1507 with a rank spread of 1-6, with Claude Opus 4.6 (high) on 1505, Claude Fable 5.1 (max) on 1504 and Meta's Muse Spark 1.2 (xHigh) on 1499, so treat the lead as first-among-equals and read the exact tie band off the live board.
• Artificial Analysis has re-based its Intelligence Index twice this month, and on v4.3 Claude Fable 5.1 (max) and GPT-6 Astra (max) share first place on 53, ahead of Claude Opus 5 on 51 and Fable 5 itself on 50, with Astra costing $3.26 per Index task against Fable 5.1's $7.63.
• Terminal-Bench has moved on too: the official board now runs v4.0, where Fable 5.1 leads on 57.9%, Opus 5 scores 51.8% and Fable 5 44.5%, so the old 83.8% figure from the 2.1 board no longer describes current terminal work.

Title

Best overall LLM

Licence

proprietary

Pick since

10 Sep 2026

Last reviewed

10 Sep 2026

Title holders to date

10

Official page

www.anthropic.com/claude/fable