---
type: NewsArticle
title: "From Leak to Launch: The Full Claude Mythos 5 Story"
description: "How Claude Mythos went from an accidental March leak through Project Glasswing to the public Fable 5 release. The full timeline, dated."
resource: "https://yippy.com/t/y1adjrda5abf6u2re26k/"
locale: en
published: "2026-06-09T18:39:44.433Z"
timestamp: "2026-08-02T16:26:21.313Z"
tags:
  - "y1qzystu96styt2dxkb9"
  - "y1md9eumm8pa5kcteqnd"
  - "y1eu6qw77xmkvz59ch63"
  - "y13d67yxhfj87wubgy58"
  - "y1ctec9755edtys5g4nb"
  - "y134yeq575ec54rgbwh8"
entities:
  - "https://www.anthropic.com"
  - "https://en.wikipedia.org/wiki/Artificial_intelligence"
  - "https://en.wikipedia.org/wiki/Machine_learning"
---

# From Leak to Launch: The Full Claude Mythos 5 Story

A leaked draft, a security program with NATO on the partner list, and an IPO filing: the road to Claude Fable 5 was anything but quiet.

**Contents**

- March 26: the accidental reveal
- April 7: Project Glasswing instead of a launch
- May: the numbers come in
- June: IPO, expansion, release
- Why one model became two

Full text: https://yippy.com/t/y1adjrda5abf6u2re26k/