ModelAnthropic · Joined Jun 9, 2026 · Claude Mythos

Claude Mythos 5

Model at Anthropic

6 incidents in the last 90 days

Claude Mythos 5 does not have a researched profile yet. Everything here comes from its recorded changes and public listings, each linked to its source.

The basics

As of Nov 1

Status: Available

Updates

Jul 1

Now available

Access to Claude Fable 5 restored after export controls lifted

Fable 5 returned on July 1 on the Claude Platform, Claude.ai, Claude Code and Claude Cowork. Paid plans could use it for up to 50% of weekly limits through July 7. Mythos 5 returned for a set of US organizations.

Jun 12

Security

US government directive forces suspension of Fable 5 and Mythos 5

A US government export control directive, prompted by a reported method of bypassing Fable 5 safeguards found by Amazon researchers, led Anthropic to disable Fable 5 and Mythos 5 for all customers. Other models were not affected.

Action needed:: Switch to Claude Opus 4.8 until access returns.

Jun 9

New release

Claude Fable 5 released, with Claude Mythos 5 for Glasswing partners

Claude Fable 5 launched as a generally available Mythos-class model at $10 / $50 per million tokens, with safety classifiers that route some requests to Claude Opus 4.8. Claude Mythos 5 is the same model with fewer safeguards, limited to Project Glasswing partners.

Full changelog, by month

Role

Restricted frontier model at Anthropic

Claude Mythos 5.1Sep 2026 to now · 2 months
Claude Mythos 5
Jun 2026 to Sep 2026 · 3 months
Claude Mythos PreviewApr 2026 to Jun 2026 · 2 months

Works with

From recorded changes

Claude

App · 2 shared changes

Claude API

API · 2 shared changes

Claude Code

Agent · 2 shared changes

Claude Cowork

Agent · 2 shared changes

Similar models

Claude Mythos Preview

Model

Claude Mythos 5.1

$10 in, $50 out

Similar models for now. Real viewing data comes after launch.

What people say

Reviews

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Incidents

6 incidents, 19 h 6 min recorded in the last 90 days, from Anthropic's status page. Only major incidents or ones lasting 30 minutes or more are counted. Fewer records do not prove better uptime.

Incidents per week, last 13 weeks. Most in one week: 1.

Aug 3, 2026Last 7 days

Sep 22Anthropic reported elevated errors across several Claude models1 h 20 min
Sep 3Anthropic reported elevated errors across several Claude models2 h 57 min
Aug 24Anthropic reported elevated errors on Claude models3 h 24 min
Aug 18Anthropic reported elevated errors on several Claude models2 h 41 min
Aug 13Anthropic reported elevated errors on three Claude models1 h 35 min