Claude Fable 5 is presented as a new 'Mythos-class' model that Anthropic (via the @claudeai account) says has been made safe for general use and surpasses the capabilities of any previously generally available Claude model; the June 9, 2026 post includes a video demonstration and a link to the announcement.
On 2026-06-09, user @EXM7777 highlighted a Claude (@claudeai) announcement introducing Claude Fable 5, described as a 'Mythos-class' model made safe for general use.
humanity will remember this day
Claude (@claudeai)
Introducing Claude Fable 5: a Mythos-class model that we’ve made safe for general use.
Its capabilities exceed those of any model we’ve ever made generally available.
Video
— https://nitter.net/claudeai/status/2064394146916229443#m