Originally published on rohitraj.tech
Anthropic shipped Claude Fable 5 on June 9, 2026 — a Mythos-class model at $10/$50 per million tokens, double the Opus 4.8 rate. Here is the developer read: the claude-fable-5 API, the Opus-4.8 safeguard fallback you must design around, the new 30-day retention rule, Fable vs Mythos, and when to wait.
Read the full version with code samples, diagrams, and architecture details: Claude Fable 5: Pricing, the API, and When to Use It vs Opus 4.8 (2026)
More engineering notes: rohitraj.tech/en/notes
