Claude Fable 5

Claude Fable 5 is Anthropic's new frontier tier, announced June 9, 2026 and positioned above Claude Opus 4.8, which stays on as the default model. The API id is claude-fable-5, priced at $10 per million input tokens and $50 per million output with no long-context surcharge. It ships a 1 million token context window by default with up to 128K output tokens, takes text and vision input, and runs adaptive thinking always on (it cannot be disabled) with effort levels spanning low, medium, high, xhigh, and max. Anthropic's launch table reports 80.3 on SWE-bench Pro, 85.0 on OSWorld-Verified, 29.3 on FrontierCode Diamond, and a GDPval-AA ELO of 1932; treat all of these as vendor-reported until independent runs land. One operational note: always-on safety classifiers can reroute flagged requests to Opus 4.8, billed at Opus rates for the rerouted portion. Available on the Claude API, Amazon Bedrock, Google Vertex, and Microsoft Foundry.