Claude Mythos release date

The short answer: three dates, not one

"Claude Mythos" is a family, so its release history has several milestones rather than a single launch day. Here is the dated timeline.

April 2026 — Mythos Preview

The first Mythos-class model shipped as the Mythos Preview, a limited release through Project Glasswing. It reached roughly 50 selected organisations in cyberdefense and critical infrastructure, including parts of the US government, at Glasswing pricing of about $25/$125 per million tokens.

June 9, 2026 — Mythos 5 and Fable 5

The generation went wider with two editions built on the same underlying model: Mythos 5, the Glasswing-only edition with classifiers lifted, and Fable 5, the public, safeguarded edition. Fable 5 reached the Claude API and major clouds, with a free window for Pro, Max, Team, and Enterprise users from June 9 to 22.

June 12, 2026 — suspension

Three days after the wide launch, a US export-control directive suspended access to both Fable 5 and Mythos 5. That suspension is still active; for the current state see the live status page.