Is Claude Mythos 5 publicly available?

No. Claude Mythos 5 — Anthropic's frontier model without the cybersecurity classifiers and safeguards added to its public sibling Claude Fable 5 — was not generally available when this guide was written on June 15, 2026, and the Mythos line still is not as of October 16, 2026. The current version is Claude Mythos 5.1 (released September 1, 2026 alongside Fable 5.1), which Anthropic lists as 'limited availability' at $10/$50 per million tokens. Access no longer runs only through account teams: you apply in Anthropic's Verification Portal (portal.anthropic.com/programs) to the Cyber Verification Program, which absorbed Project Glasswing members, or join the waitlist for the Life Sciences Verification Program.

What's the difference between Claude Mythos 5 and Claude Fable 5?

Same underlying model, different safety layer. Both share the same core weights and frontier capabilities — that's why Anthropic priced them identically at $10/$50 per million input/output tokens. Fable 5 ships with additional cybersecurity classifiers, biological-weapons restrictions, and content safeguards added on top; Mythos 5 ships without those classifiers, so it can answer dual-use questions that Fable 5 refuses. The capability ceiling is the same; the refusal surface is different. Anthropic positions Mythos 5 for use cases where the safeguard layer would create false-positive refusals (e.g., legitimate cybersecurity red-teaming) and grants access only to vetted partners.

How do I apply for Project Glasswing access?

October 2026 update: Project Glasswing members have been moved into Anthropic's updated Cyber Verification Program (CVP), and new applicants apply there instead. Sign in to the Verification Portal (portal.anthropic.com/programs), open Programs, choose Cyber Verification Program and select Apply; Anthropic aims to send a decision or a request for more information within seven business days. Organizations apply once; independent researchers, maintainers and bug bounty hunters can apply as individuals on a paid plan, but only for Defense Access (Red Team and Specialized Access are for organizations). On AWS, Google Cloud or Microsoft Foundry you link the cloud account in the portal, and Mythos access follows approval by about five business days. The original June 2026 description follows: Project Glasswing is Anthropic's cybersecurity-partner program. You can't apply through a public form. The path is: (1) Have an existing Anthropic Enterprise or AWS/Vertex AI relationship. (2) Contact your account team and request consideration for Project Glasswing. (3) Anthropic will assess organizational fit — typical accepted partners are established cybersecurity firms, government security agencies, and major financial institutions with active red-team programs. (4) If accepted, sign supplemental agreements covering responsible use, incident reporting, and audit access. Lead time from initial request to API access is typically 4–12 weeks. Anthropic does not publish acceptance criteria; rejection rates are reportedly high.

What should I use instead if I can't get Mythos 5 access?

For 95%+ of workloads, Claude Fable 5 is the right answer — same core capability, just with safeguards. The Fable 5 refusal rate on legitimate developer queries is low; in published evaluations, Fable 5 refuses roughly 3–5% more queries than Mythos 5, and most of those refusals are appropriate. If you hit a specific Fable 5 refusal on a legitimate workflow, document the case and raise it with Anthropic — they have a process to whitelist specific use cases without granting full Mythos access. If your use case is security work blocked by Fable's classifiers, apply to the Cyber Verification Program in Anthropic's Verification Portal; if it is biology research, join the Life Sciences Verification Program waitlist (claude.com/form/life-sciences-verification-program). Both grant Mythos, Opus and Sonnet access with adjusted safeguards as of October 2026. The refusal-rate figure above was reported in June 2026 and has not been re-confirmed.

How do I get Claude Mythos 5.1 access in October 2026?

Apply through Anthropic's Verification Portal (portal.anthropic.com/programs). For security work, the Cyber Verification Program gives verified organizations, and individuals on a paid plan at the Defense tier, access to Claude Mythos 5.1, Opus 5.5 and Sonnet 5.5 with reduced cyber classifiers; Anthropic aims to answer within seven business days. For biology, the Life Sciences Verification Program (beta, teams and institutions first) grants Mythos, Opus and Sonnet access with more permissive biology safeguards. Once approved, Mythos 5.1 costs $10/$50 per million tokens on the API and, on Pro and Max plans, follows the same usage rules as Fable 5.1.

Quick Answer

How to Get Claude Mythos 5 Access (October 2026)

Published: June 15, 2026 • Updated: October 16, 2026

How to Get Claude Mythos 5 Access (June 2026)

Claude Mythos 5 is Anthropic’s frontier model without the cybersecurity classifiers and content safeguards that ship with its sibling Claude Fable 5. It’s not publicly available. Access is restricted to approved partners — mostly through Project Glasswing for cybersecurity and a separate program for biology/chemistry research. This page explains exactly who can access it, how to apply, and what to use instead if you can’t.

Last verified: October 16, 2026.

What changed as of October 2026

Mythos 5.1 replaced Mythos 5 as the current Mythos model. It launched September 1, 2026 with Claude Fable 5.1. Anthropic’s pricing page lists both Mythos 5.1 and Mythos 5 as “limited availability” at $10/$50 per million tokens; Mythos 5.1 cache hits cost $0.25 (Mythos 5: $1). See what Mythos 5.1 is.
There is now a self-service application. How do I get Claude Mythos 5.1 access in October 2026? Apply in Anthropic’s Verification Portal (portal.anthropic.com/programs) to the Cyber Verification Program, which now covers Mythos 5.1, Opus 5.5 and Sonnet 5.5 and absorbed Project Glasswing members, or join the Life Sciences Verification Program waitlist for biology work. CVP decisions are targeted within seven business days, not the 4–12 weeks this guide originally estimated.
Individuals can qualify. Independent researchers, maintainers and bug bounty hunters can apply on a paid plan, but only for the Defense Access tier.
Subscription plans now include Mythos for approved users. On Pro and Max, Mythos 5.1 follows the same usage rules as Fable 5.1.
Cloud access changed. After approval you link your AWS, Google Cloud or Azure account in the portal; Mythos access follows about five business days later. On Amazon Bedrock, CVP is available only to customers with Enterprise Frontier Safeguards.

The sections below are the original June 15 guide; statements that are now out of date are marked.

TL;DR

Mythos 5 is NOT generally available. No public sign-up.
Path 1: Cybersecurity. June 2026: Project Glasswing via your account team. October 2026: the Cyber Verification Program in Anthropic’s Verification Portal.
Path 2: Biology research. June 2026: a trusted-access program, contact as described below. October 2026: the Life Sciences Verification Program waitlist.
For everyone else: Use Claude Fable 5 — same core capabilities, with safeguards. Available on Claude API, AWS Bedrock, Google Vertex AI, Microsoft Foundry from June 9, 2026.

What Mythos 5 actually is

Claude Mythos 5 and Claude Fable 5 were announced together on June 9, 2026, as the first models in Anthropic’s new Mythos-class tier — a capability class that sits above the Opus class. Anthropic’s framing: Mythos-class models have crossed a threshold where additional safeguards became necessary for general release.

Same model, two configurations:

	Claude Fable 5	Claude Mythos 5
Public availability	Yes (June 9, 2026)	No — restricted partners only
Core weights	Same	Same
Cybersecurity classifier	Yes	No
Bio/chem additional restrictions	Yes	Reduced
Standard content safeguards	Full	Reduced
API model ID	`claude-fable-5`	`claude-mythos-5`
Price	$10/$50 per Mtok	$10/$50 per Mtok
Cache read	$1/Mtok	$1/Mtok
Where to access	Claude API, AWS Bedrock, Google Vertex AI, Microsoft Foundry	Restricted-access channels only

Anthropic has been explicit that the capability ceiling is identical. The difference is the safeguard layer that screens model outputs.

Path 1: Project Glasswing (cybersecurity)

Project Glasswing is Anthropic’s program for trusted cybersecurity partners. The named focus is enabling legitimate offensive-security research — penetration testing, red-team exercises, vulnerability research — that the public Fable 5 safeguards would block as false positives.

Who has been accepted (publicly disclosed or reported):

Major cybersecurity firms with established red-team practices
Select cloud providers and security vendors
Government cybersecurity agencies in allied countries (subject to additional review)
Large financial institutions with internal red-team capability

How to apply (October 2026): sign in to the Verification Portal, open Programs, choose “Cyber Verification Program” and select “Apply”. One application per organization; Anthropic places you at the highest tier it can verify (Defense, Red Team or Specialized Access) and aims to reply within seven business days. Existing Project Glasswing members do not need to reapply.

How to apply (June 2026 process, superseded):

Have an existing Anthropic Enterprise account, or AWS / Google Cloud relationship that includes Claude access.
Contact your account team and request consideration for Project Glasswing.
Provide a written description of your security research use case, organizational red-team program, and proposed safeguards.
Sign Anthropic’s supplemental Mythos-access agreement covering responsible use, incident reporting, and ongoing audit cooperation.
Wait 4–12 weeks for review.

What disqualifies you: No documented red-team / security research program. Individual researchers without organizational backing. Use cases that look like general-purpose access dressed up as security research.

Path 2: Biology and chemistry research

Anthropic has a separate trusted-access program for biology and chemistry researchers. The bar is even higher because Mythos 5’s reduced bio safeguards are the most carefully gated part of the access policy.

Typical accepted profile:

Established academic research labs at universities with institutional biosafety review
Pharmaceutical companies with internal compliance programs
Public-interest biology research organizations

How to apply (October 2026): Anthropic now runs the Life Sciences Verification Program (beta). Join the waitlist at claude.com/form/life-sciences-verification-program; applicants are reviewed on research credentials, security standards and ethical oversight, then receive a “Standard Use” or “High-risk Use” grant usable in Claude Science, Claude.ai, Claude Code and the API. It opens to teams and institutions first, with individual Pro and Max plans to follow.

How to apply (as described in June 2026; the email route below was not confirmed by an Anthropic primary source and is superseded by the program above):

Email [email protected] with a written research protocol, IRB or equivalent biosafety review documentation, and institutional affiliation.
Provide a clear scientific justification for why reduced safeguards are necessary (i.e., why Fable 5’s defaults block legitimate research).
Anthropic reviews against published criteria and may request additional documentation.
If accepted, sign a supplemental research-use agreement.

This path is reportedly stricter than Project Glasswing. Expect rejections for individual researchers without institutional review processes.

Path 3: What Anthropic has hinted may come later

In its June 9, 2026 announcement, Anthropic signaled that additional restricted programs may follow in areas including:

AI safety research labs
Frontier AI evaluation organizations
Government scientific research institutions

These programs did not exist publicly as of June 15, 2026. By October 2026 Anthropic had opened the Cyber Verification Program and the Life Sciences Verification Program to applications. Anthropic’s framing is that it will open additional access channels as it gains operational experience with Mythos 5 and as the underlying safety classifiers mature.

What to use if you can’t get access

For 95%+ of legitimate use cases, Claude Fable 5 is the right answer:

Same frontier capabilities (80.3% SWE-Bench Pro, leading the Artificial Analysis Intelligence Index)
Same price ($10/$50 per Mtok)
Same 1M token context window
Generally available on Claude API, AWS Bedrock, Google Vertex AI, Microsoft Foundry from day one

The published refusal-rate delta between Fable 5 and Mythos 5 on developer workloads is small — Fable 5 refuses roughly 3–5% more queries, and most of those refusals are appropriate (genuine policy violations) rather than false positives.

If you hit a specific Fable 5 refusal on a legitimate workflow:

Document the prompt, response, and your use-case justification.
Email your Anthropic account contact (or [email protected]).
Anthropic has a per-use-case whitelisting process that can grant exceptions without full Mythos access. Lead time: 1–4 weeks.

This is the right path for most teams. Full Mythos access is overkill if you only have a handful of false-positive refusals per month.

Common misconceptions

“Mythos 5 is more capable than Fable 5.” False. Same core weights, same capabilities. Mythos has fewer refusals; that’s the only meaningful difference for end-user experience.
“I can sign up for Mythos with a credit card.” Still false, but closer than in June: since the updated Cyber Verification Program, anyone with an Anthropic account can apply in the Verification Portal, and individuals on a paid plan can qualify for Defense Access. Access still depends on verification.
“AWS or Google Cloud sells Mythos.” Partial. As of October 2026, approved organizations link their AWS, Google Cloud or Azure account in the Verification Portal and get Mythos there about five business days after approval; on Amazon Bedrock, CVP is limited to customers with Enterprise Frontier Safeguards.
“Mythos 5 doesn’t have any safety filters.” False. Mythos 5 retains Anthropic’s baseline constitutional AI training and the Acceptable Use Policy. What’s removed is the additional cybersecurity classifier and certain expanded restrictions added to Fable 5.

Pricing comparison

Cost item	Mythos 5	Fable 5	Opus 4.8
Input	$10/Mtok	$10/Mtok	$5/Mtok
Output	$50/Mtok	$50/Mtok	$25/Mtok
Cache read	$1/Mtok (Mythos 5.1: $0.25)	$1/Mtok (Fable 5.1: $0.25)	$0.50/Mtok
Batch discount	50%	50%	50%
Plan inclusion (June 2026)	None (credits-only)	Pro/Max/Team until June 22, then credits	Pro/Max/Team
Plan inclusion (Oct 2026)	Mythos 5.1 for verified users: same rules as Fable 5.1 on Pro/Max	Fable: usage credits on Pro, up to 50% of weekly limits on Max	Pro/Max/Team

In June, Mythos 5 had no plan-included access. As of October 16, 2026, Anthropic says Mythos 5.1 follows the same usage rules as Fable 5.1 on Pro and Max plans for organizations approved through the Cyber Verification Program.

Timeline expectations

Cyber Verification Program (October 2026): decision targeted within seven business days; Mythos on third-party clouds about five business days after approval.
Project Glasswing application (June 2026 estimate, superseded): 4–12 weeks from initial request to API access.
Research program application: 6–16 weeks; expect more documentation back-and-forth.
Per-case Fable 5 whitelisting: 1–4 weeks (the right answer for most narrow use cases).
Wait-and-see for broader access: No public timeline. Anthropic has historically expanded restricted programs incrementally; expect months to quarters, not days.

Anthropic’s restricted-access programs change over time. Confirm current criteria with your Anthropic account team before basing a procurement decision on this guide.