Claude Fable 5 is Anthropic's most capable model — a Mythos-class system that sits above Opus on hard reasoning, long-context work, and agentic tool use.
Why Fable 5
Fable 5 keeps the Claude qualities developers rely on — steerable tone, careful reasoning, strong instruction-following — and pushes the ceiling on multi-step agents, large-codebase edits, and dense analytical work.
The fastest way to try it
You don't need a new SDK or a migration. Through OneHop, Fable 5 is a drop-in endpoint:
- Create an account — new accounts get $10 in free credit, no card required.
- Point your existing Anthropic SDK at OneHop's base URL.
- Call
claude-fable-5like any other model.
Same SDK, 30% below list price, running on the most powerful Claude available.