fable5-best-practice

Treat Claude Fable 5 as a long-horizon decision and orchestration model, not a faster chat model. Use it when judgment, decomposition, verification, or sustained tool use matters enough to justify premium cost and latency.

Current Fable facts are volatile. Before giving pricing, availability, retention, fallback, or platform-specific API advice, re-check official Anthropic docs. As of 2026-07-09, official docs describe Fable 5 as a high-autonomy model with always-on adaptive thinking, high as the normal starting effort, higher price than Opus/Sonnet, and a 30-day data-retention requirement that makes it unavailable under zero data retention arrangements.

Core rule

Use the cheapest model that can reliably meet the acceptance criteria.