Reference
Mythos-class model comparison
How the Mythos-class models line up against each other and against Claude Opus 4.8. Availability for Fable 5 and Mythos 5 reflects the current live verdict — Fable 5 & Mythos 5: access suspended. Every cell is sourced; hover a model name for its primary reference.
Updated Jun 30, 2026.
| Field | Claude Mythos Preview | Claude Fable 5 | Claude Mythos 5 | Claude Opus 4.8 |
|---|---|---|---|---|
| Tier | Mythos-class (above Opus) | Mythos-class (above Opus) | Mythos-class (above Opus) | Opus (flagship general) |
| Released | April 2026 | June 9, 2026 | June 9, 2026 | Available |
| Context | 1M tokens | 1M tokens | 1M tokens | 200k–1M tokens |
| Max output | Up to 128k | Up to 128k | Up to 128k | Up to 64k |
| Input price | ~$25 / M (Glasswing) | $10 / M (after intro) | $10 / M (after intro) | Standard Opus pricing |
| Output price | ~$125 / M (Glasswing) | $50 / M (after intro) | $50 / M (after intro) | Standard Opus pricing |
| Availability | Project Glasswing only (~50 orgs at launch) | Suspended (US export-control directive) | Suspended (US export-control directive) | Generally available |
| Safeguards | Glasswing program controls | Safety classifiers (cyber, bio/chem, distillation) reroute <5% of sessions to Opus 4.8 | Same model as Fable 5 with safety classifiers lifted | Standard Claude safety stack; receives rerouted Fable 5 sessions |
| Access path | Project Glasswing invitation | Claude API, AWS, Bedrock, Google Cloud, Microsoft Foundry | Project Glasswing limited release | Claude API, claude.ai, cloud platforms |
Linked cells point to the source for that fact. Pricing shown is post-introductory unless noted. For deeper definitions and benchmarks, see mythoslm.ai. Not affiliated with Anthropic.