Mythos-class · Released June 9, 2026
Available againClaude Fable 5
Anthropic's first Mythos-class model — the top published SWE-Bench Pro score, long-horizon autonomy, and expert reasoning. Suspended June 12 under US export controls, it returned globally on July 1, 2026.
- 80.3%
- SWE-Bench Pro — top public-model score
- 1M
- token context window
- $10 / $50
- per million input / output tokens
- <5%
- of sessions routed to Opus 4.8 safeguards
Why Claude Fable 5 matters
- Mythos-class — a tier above Opus at launch, with capabilities that exceeded anything Anthropic had previously made generally available.
- 80.3% on SWE-Bench Pro, the highest public score for agentic coding, plus a 1M-token context and up to 128K output.
- Back online globally as of July 1, 2026 after a June 12 US export-control suspension — redeployed with new safety classifiers.
- Some routine coding and debugging requests temporarily fall back to Opus 4.8 while Anthropic tunes the new classifiers to cut false positives.
Claude Fable 5 specifications
| — | Claude Fable 5 |
|---|---|
| API model ID | claude-fable-5 |
| Release date | June 9, 2026 |
| Context window | 1,000,000 tokens |
| Max output | 128K tokens |
| Pricing (in / out per M) | $10 / $50 per M |
| SWE-Bench Pro | 80.3% (SWE-Bench Pro) |
| Availability | Available again (July 1, 2026) — API, Claude apps, AWS, Google Cloud, Microsoft Foundry, GitHub Copilot, OpenRouter |
Restored globally on July 1, 2026 for Pro, Max, Team, and select Enterprise plans — included within up to 50% of weekly usage limits through July 7, then via usage credits. Source: Anthropic.
Claude Fable 5 vs Claude Mythos 5
Fable 5 and Mythos 5 share the same underlying model. Fable 5 ships with strict safety classifiers and is available to everyone; Mythos 5 has safeguards lifted in areas like cybersecurity and is restricted to vetted defenders through Project Glasswing.
Read Fable 5 vs Mythos 5Claude Fable 5 FAQ
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