Claude Fable 5.1

Claude Fable 5.1 sits above Opus in Anthropic's price list, released 2026-09-01. OpenRouter lists $10 per million input tokens and $50 output, a 1,000,000-token context, and text, image and PDF input. That makes it more than twice the input price of Opus 5.5. It is closed and proprietary, so there are no weights. Anthropic's Max plan notes say Fable usage is included up to half the weekly limit, which we cover in our Claude Code entry. We would suggest it only for the hardest tasks, where a team has already seen smaller models fail and can show that the extra spend pays for itself. The limit is cost and access: at this price, a long agent run can add up quickly, so set a budget before you start. Prices and specifications come from the OpenRouter listing we checked on 31 October 2026, and we have not tested the model ourselves.