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Announcement · June 9, 2026

Claude Fable 5 and Mythos 5 announced

Anthropic introduced Fable 5 for general use and Mythos 5 with restricted access for selected infrastructure defenders.

Why it matters

Different access regimes show how risk assessment affects model deployment.

The source records a temporary suspension on June 12 and redeployment on July 1; this record concerns the initial June 9 announcement.

Event record

Event date: June 9, 2026
Timeline date: Event date
Verification: Sources gathered automatically · September 11, 2026
ID: evt-0034

Sources

primary Claude Fable 5 and Claude Mythos 5
Anthropic · Published June 9, 2026

Records that link to this one

Related Fable 5 biology-safeguard update
The update concerns the model this record announces.
Extends Export control reaches the model itself, not the chips
The same two models, released three days earlier; the company's later post names the release day as Tuesday 9 June.
Redeploying Fable 5