Unverified Anthropic Model 'Fable 5' Claimed to Outperform Opus 4.8

A Reddit post describes an unreleased Anthropic model lineup — Claude Mythos behind a restricted program called Project Glasswing, with Fable 5 as the public-facing version — and claims Fable 5 completed all five complex tasks where Opus 4.8 failed. No official Anthropic announcement or verifiable benchmarks accompany these claims.