Anthropic released Claude Fable 5, a new model tier above Opus, on June 9. The model ID is claude-fable-5; pricing is $10 per million input tokens and $50 per million output. It posts state-of-the-art results on nearly all tested benchmarks, including the top frontier score on Cognition's FrontierCode.
Mythos 5 — the same model with safeguards lifted in specific areas — is restricted to Project Glasswing partners and select biology researchers.
Fable 5 is available immediately on the API and consumption-based Enterprise, and powers Claude Code. The API surface matches Opus 4.7/4.8, with one addition: an explicit thinking: {"type": "disabled"} now returns 400 — omit the field instead.
Details in the announcement; practical orientation in our guide.