What Happened
On 2026-06-09, Anthropic launched Claude Fable 5 and Claude Mythos 5, using different safeguards and access policies for the same underlying model.
Why It Matters
The release made capability-dependent deployment central to a model family: broadly accessible agentic intelligence and restricted specialist access were offered separately. The subsequent access interruption became part of its deployment history.
Technical Details
Fable could route flagged requests to Opus 4.8; Mythos was initially limited to selected Glasswing partners. Both launched at $10 input and $50 output per million tokens. Access was suspended on June 12; Fable's global access was restored July 1. This later interruption does not change the initial launch date.