Anthropic · Claude
Claude Fable 5
CurrentActiveFirst publicly available Mythos-class model (above Opus); Mythos 5 weights with safety classifiers active. 1M context, $10/$50, highest benchmarks of any GA model. Refusals return stop_reason refusal; mandatory 30-day retention.
About this version
Claude Fable 5 is the flagship model in Anthropic’s Claude family, released on 9 June 2026 as the first publicly available Mythos‑class system, positioned above the earlier Opus line. It runs on Mythos 5 weights with active safety classifiers and supports a one‑million‑token context window, while enforcing a mandatory 30‑day data retention policy and returning refusals with a stop_reason of “refusal.”
- API string
- claude-fable-5
- Context window
- 1M ctx
- Knowledge cutoff
- Jan 1, 2026
- Tier
- Flagship
- Released
- Jun 9, 2026
Release & change timeline
1 event- Release
Claude Fable 5 released
First publicly available Mythos-class model; Mythos 5 weights with safety classifiers active.
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