SYS://REGISTRY
LEDGER/Anthropic/claude-fable-5-1
SPEC DATASHEET // claude-fable-5-1
Anthropic/RELEASED Sep 1, 2026

Claude Fable 5.1

FRONTIER FLAGSHIP #1

Released Sept 1, 2026; Anthropic's reigning flagship for agentic coding and knowledge work. Features a 75% reduction in cache read costs ($0.25/M tokens) and 52.6% on Terminal-Bench-Science.

Context
1,000,000 tokens
Architecture
Frontier MoE (Adaptive Thinking)
Pricing (1M)
$10 in / $50 out
License
Proprietary API / Cloud Foundry
Verified Benchmark Suite
SWE-BENCH
78.4%
GPQA DIAMOND
74.8%
Quickstart Snippet
curl -s https://modelregistry.tirup.in/api/cli?model=claude-fable-5-1