Maithra Raghu(@maithra_raghu):We partnered with @AnthropicAI to evaluate @claudeai Fable 5.1 pre-launch on FrontierFinance! Fable 5.1 becomes the best performing frontier model by a wide margin, scoring 55.9% compared to 49.2% for Fable 5 (the prior best performing frontier model.) This gain largely comes from Fable 5.1 carrying out more and better tool calls, e.g. calling and anchoring better on authoritative sources. The increased tool calls does come with increased cost though -- we observe Fable 5.1 is about 1.7x as expensive as Fable 5. Exciting results and lots more work ahead to continue advancing agentic capabilities!

2026.09.01 18:26

We partnered with @AnthropicAI to evaluate @claudeai Fable 5.1 pre-launch on FrontierFinance! Fable 5.1 becomes the best performing frontier model by a wide margin, scoring 55.9% compared to 49.2% for Fable 5 (the prior best performing frontier model.) This gain largely comes from Fable 5.1 carrying out more and better tool calls, e.g. calling and anchoring better on authoritative sources. The increased tool calls does come with increased cost though -- we observe Fable 5.1 is about 1.7x as expensive as Fable 5. Exciting results and lots more work ahead to continue advancing agentic capabilities!