General users
Evaluate Fable 5.1 or another generally available Claude model. Mythos is not an upgrade selectable by a consumer plan.
Anthropic restricted model · checked September 2, 2026 Previous generation · 5.1 is current
Quick answer
Mythos 5 is now the history behind the 5.1 trusted-access path.
The 5 generation paired Mythos with Fable under different safeguards. Anthropic now uses that same shared-model design for Mythos 5.1, with separate trusted programs for vetted cyber and life-sciences work.
Verified provider record
Provider status
Previous restricted generation. Anthropic now positions Mythos 5.1 as the current trusted-access profile for vetted cybersecurity and life-sciences organizations; there is still no self-serve consumer path.
Claude API ID
claude-mythos-5. The identifier does not grant access without organization approval and provisioning.
Underlying model
The same underlying model, specifications, and published pricing as Claude Fable 5, with a different approved safeguard profile. Anthropic documents the same shared-model relationship for the current 5.1 pair.
Context and output
Anthropic says Mythos shares Fable's specifications: 1 million token context and up to 128,000 output tokens.
Published API price
$10 per million input tokens and $50 per million output tokens were published for approved Mythos 5 access. Do not infer Mythos 5.1 pricing or entitlement from this historical record; verify the trusted-access agreement.
Flowith access
Not asserted here. Restricted provider access does not establish a Flowith model mapping.
Access boundary
Approval is part of the model contract
Cyber defenders
Anthropic says its Cyber Verification Program will include Mythos-class access for vetted defensive-security work. Program approval and provisioning remain separate from a model name.
Biology researchers
Anthropic says the Life Sciences Verification Program has enrolled initial participants and is designed to provide Mythos 5.1 with safeguards tailored to professional research and development.
Cloud customers
Contact the governing provider and account team. A visible model name, old Mythos 5 ID, or Fable 5.1 cloud listing is not proof of Mythos 5.1 entitlement.
Governance checks before access
- Mythos changes safeguards only within an approved program and domain; Mythos 5.1 is not an unrestricted public model.
- Cyber Verification and Life Sciences Verification have distinct purposes. Access terms, acceptable use, logging, incident response, and human oversight belong in the actual program agreement.
- Enterprise Frontier Safeguards changes the general frontier-model data architecture, but Anthropic's launch specifically describes transition ZDR for eligible Fable 5 and Fable 5.1 customers. Do not assume an old Mythos 5 contract inherits EFS.
- Where EFS applies, customer-owned storage, customer-managed encryption keys, and automated review are each opt-in; customer teams receive flags and no Anthropic human review is required.
- Do not infer that a trusted-access approval, cloud listing, provider price, or API identifier makes Mythos 5 or Mythos 5.1 available in Flowith.
Official sources
- Fable 5.1 and Mythos 5.1 launch — current generation, shared base model, trusted programs, safeguards, and availability.
- Enterprise Frontier Safeguards — phased rollout, customer-controlled storage, opt-in controls, review ownership, supported surfaces, and cloud costs.
- Anthropic launch — shared model, safeguards, trusted access, pricing, and initial availability.
- Anthropic redeployment update — current restricted restoration and safeguard revisions.
- Claude model overview — invitation-only status, IDs, shared specifications, and account-team route.
- Covered-model retention policy — scope, 30-day retention, review controls, and exceptions.
Continue by decision intent
Fable vs Mythos Compare the shared model, safeguards, fallback, approval, and retention boundaries. Claude Fable 5 Use the broadly available safeguarded profile for general agentic and knowledge work. Fable plans and migration Separate the historical Fable 5 plan record from current Fable 5.1 API, cache-price, and cloud checks. Claude Opus 5 Consider a generally available enterprise model when restricted access is not appropriate.
Claude Mythos 5 questions, answered
Claude Mythos 5 is Anthropic's previous restricted profile of the same underlying model used by Claude Fable 5. Anthropic now describes Mythos 5.1 as the current trusted-access profile, available to vetted cybersecurity and life-sciences organizations through separate verification programs.
No. Mythos remains a trusted-access path rather than a consumer upgrade. A current applicant must use the relevant Cyber Verification or Life Sciences Verification program and receive explicit provisioning.
Anthropic names claude-mythos-5, but the identifier is usable only after the organization receives approval, provisioning, and the relevant platform entitlement.
Anthropic says they share the same underlying model, specifications, and published pricing. The primary difference is the safeguard and access profile.
The historical covered-model policy applied 30-day retention in some zero-data-retention arrangements. Anthropic has since announced a phased Enterprise Frontier Safeguards architecture, but its transition statement specifically names eligible Fable 5 and Fable 5.1 customers. Verify the exact Mythos contract rather than applying either rule universally.
Target the current Mythos 5.1 program described by Anthropic. The older Mythos 5 ID and program history do not establish current eligibility, endpoint access, pricing, or safeguard scope.
This page does not claim a Flowith mapping. Mythos provider access is restricted, and any Flowith availability would require separate first-party confirmation.