Claude Mythos 5
Claude Mythos 5 Overview
Claude Mythos 5 is the restricted counterpart to Claude Fable 5 — the same underlying model with some safeguards lifted, available only to approved customers in Anthropic’s Project Glasswing trusted-access program.
Access note: Claude Mythos 5 is not a public self-serve model. You cannot sign up for it through the Claude app or standard API billing. Access is limited to approved customers in Anthropic’s Project Glasswing program. For a widely available model with the same underlying capability, see Claude Fable 5.
Claude Mythos 5 (claude-mythos-5) launched alongside Claude Fable 5 on June 9, 2026. The two share the same underlying model; the difference is deployment. Fable 5 ships with safety safeguards that make it suitable for general release. Mythos 5 has some of those safeguards lifted in specific areas, so Anthropic restricts who can use it. This page is an informational overview — it covers what Mythos 5 is, how access works, and how it relates to the rest of the Claude lineup.
ClaudeAIHub. For official information, see Anthropic’s model overview.
How Mythos 5 Relates to Fable 5
Think of Mythos 5 and Fable 5 as two deployments of one model. Fable 5 is the “made safe for general use” version: its classifiers route a small share of high-risk requests (offensive cyber, broad biology/chemistry, distillation attempts) to Claude Opus 4.8. Mythos 5 lifts some of those restrictions for vetted organizations whose legitimate work — such as defensive cybersecurity or biomedical research — requires capabilities the general release deliberately constrains. Specs are the same: 1M token context window, 128k max output, adaptive thinking always on, and listed pricing of $10 input / $50 output per MTok for approved customers.
What Is Project Glasswing?
Project Glasswing is Anthropic’s trusted-access program for deploying less-restricted frontier models to vetted partners. Mythos 5 is deployed initially through a collaboration with the US government, with a planned expansion of trusted access to cybersecurity organizations and biomedical researchers. Mythos 5 succeeds the earlier invitation-only Claude Mythos Preview (claude-mythos-preview), which Anthropic says will be retired after Mythos 5 becomes available to its users.
Who Can Access Claude Mythos 5?
- Not generally available — there is no self-serve sign-up in the Claude app or API console
- Approved Project Glasswing customers — initially government-affiliated cybersecurity and infrastructure partners
- Select biology researchers via the trusted-access program, with planned expansion to more cybersecurity organizations and biomedical researchers
- How to ask: Anthropic directs interested organizations to their Anthropic, AWS, or Google Cloud account team
For everyone else, Claude Fable 5 is the way to use this model generation — generally available via the Claude API and, on a staged basis, through Claude subscription plans. See Claude Models Explained for the full lineup.
Frequently Asked Questions
What is Claude Mythos 5?
Claude Mythos 5 is a restricted-access Anthropic model launched June 9, 2026. It shares the same underlying model as Claude Fable 5 but has some safeguards lifted, so access is limited to approved customers in Anthropic’s Project Glasswing trusted-access program.
Is Claude Mythos 5 available to the public?
No. Claude Mythos 5 is not a public self-serve model. It is offered in limited availability to approved Project Glasswing customers — initially via a US government collaboration, with planned expansion to vetted cybersecurity organizations and biomedical researchers.
Is Mythos 5 the same as Fable 5?
They share the same underlying model. Fable 5 is the widely released version with safety safeguards; Mythos 5 has some safeguards lifted in specific areas and is restricted to trusted-access partners.
What is Project Glasswing?
Project Glasswing is Anthropic’s trusted-access program for deploying less-restricted frontier models to vetted organizations, such as government cybersecurity partners and biomedical researchers. Mythos 5 and the earlier Mythos Preview are deployed through it.
How much does Mythos 5 cost?
Anthropic’s pricing page lists Claude Mythos 5 at per million input tokens and per million output tokens — the same as Claude Fable 5 — for approved customers. There is no public purchase path.
Can I use Mythos 5 in Claude?
No. Mythos 5 does not appear in the Claude app’s model picker and cannot be enabled on Free, Pro, Max, or Team plans. Claude Fable 5 is the generally available model from the same generation.