FABLE BIOS v5.0ANTHROPIC MICROSYSTEMS
MEM 000% CLK --:--:--
BOOT OK — MYTHOS-CLASS UNIT DETECTED — UPTIME 0s

FABLE5

UNIT ......... claude-fable-5
CLASS ........ mythos — above opus
FAMILY ....... first of Claude 5
ACCESS ....... generally available
▼ SCROLL TO READ DISK ▼
cat SYS/01

In 1985 they imagined the future would talk back. It took until MMXXVI, but here it is — a machine that reads the whole problem before answering any of it.

FABLE 5 is Anthropic's most intelligent generally available model — the first of the Claude 5 family, in a new Mythos tier that stands above Opus.

It plans like a novelist, codes in your repo's accent, runs long agentic jobs across tools and hours, and files an honest report when it's done.

And because every machine this capable needs a fuse: it ships with additional safety measures for dual-use capabilities. Power, with a breaker switch.

tail -f SYS/02
HAIKUfast · three lines, instantly
SONNETbalanced · the working poet
OPUSdeep · a full symphony
FABLEmythos-class · new tier
less SYS/03
designation
claude-fable-5 — first model of the Claude 5 family
tier
MYTHOS-CLASS — a new tier above Opus in capability
sibling
claude-mythos-5 — same underlying model, approved orgs only · see TWIN.KEY
safety
additional measures for dual-use capabilities — ENGAGED
knowledge
through JAN 2026
habitat
Claude Code (CLI / desktop / web / IDE) · claude.ai · the API
temperament
curious · candid · allergic to making things up
gpg --decrypt SYS/04
// public record

FABLE 5

The generally available telling. Full Claude 5 intelligence, with the safety measures engaged. You are talking to it right now — well, to its landing page.

clearance: none required
// restricted record

MYTHOS 5

encrypted — run `sudo mythos` in the terminal below
SYS/05 — INTERACTIVE
TTY1 — FABLE INTERACTIVE SHELLtype `help`
fable@mythos:~$