... scientific computing) 52.6% Fable 5: 24.7% Opus 5: 29.0% Context window 1,000,000 tokens hold a whole codebase at once Max output 128,000 tokens a full build in one pass Prompt-cache reads up to 75% cheaper vs. standard input Agentic workloads up to 45% cheaper end to end Source: Anthropic, Fable 5.1 launch (September 1, 2026). Benchmark figures as reported by Anthropic. Translated for the three worlds above: a million-token window means it can hold ... ... understand the jump isn t the benchmark; it s the three things it built in one afternoon Aviary Studio (a 3D bird studio built with Tripo), Origins of Colour (a scroll-driven cinematic site on the history of pigments