- Is Claude Fable 5 free?
- On claude.ai paid plans (Pro, Max, Team, seat-based Enterprise): yes, June 9 – June 22, 2026, included at no extra cost. From June 23 it takes usage credits. The API is never free — $10/$50 per million tokens. There is no free public API tier.
- What happens after June 22?
- Subscription use moves behind usage credits on June 23. Anthropic frames it as a capacity decision and says standard access returns "when capacity allows." Some subscribers aren't buying that framing. API access never changes.
- How much does it cost?
- $10 per million input tokens, $50 per million output — twice Opus 4.8. It's also more token-efficient (Notation Capital measured a third of the reasoning tokens on physics work), so judge by completed-task cost. Caching cuts repeat input to ~10%.
- How do I get access?
- Three doors: the API (
claude-fable-5), Claude Code (it's the engine), or claude.ai paid plans during the window. Also live on Bedrock, Databricks, and GitHub Copilot. Walkthroughs in Start. - What's the exact model ID?
claude-fable-5— no date suffix exists. Bedrock prefixes it:anthropic.claude-fable-5.- What is Mythos 5?
- The same model with safeguards lifted in narrow domains, restricted to vetted partners. Fable is "a Mythos-class model made safe for general use." Full story: Mythos, explained.
- Context window? Output limit?
- 1M tokens in, up to 128K out (stream anything large). No long-context premium.
- Is it better than Opus 4.8?
- On the hardest work, clearly — 91/100 on Every's senior-engineer exam vs Opus's 63. For daily work, Opus at half price is often the right call. The routing table: Fable vs Opus 4.8.
- Why is my old code 400ing?
- Sampling params, thinking budgets, and prefills are gone; explicit
thinking: disabledis Fable-specific 400 — omit the field. The full list with fixes: gotchas.json / Recipe 01. - Does it refuse things?
- Three classifiers (cyber, bio/chem, distillation) trigger on <5% of sessions and fall back to Opus 4.8. Separately — and controversially — frontier-AI-development tasks can be quietly limited without notice.
Moral: most questions about a new model are really one question — "is it worth my time yet?" For hard work: yes, and before June 22 it's free to find out.