Claude Mythos 5.1 costs $10 per million input tokens and $50 per million output tokens. It has a one-million-token context window and can return up to 128,000 tokens in one response.
Claude Mythos 5.1 release date
How much does Claude Mythos 5.1 cost?
Claude Mythos 5.1 specifications
Is Claude Mythos 5.1 available in Nigeria and Africa?
How to access Claude Mythos 5.1
Where can approved organisations use Mythos 5.1?
Claude Mythos 5.1 vs Claude Fable 5.1
On Tuesday, Anthropic released Claude Mythos 5.1, its latest model that serves approved professionals in cybersecurity and life science research and can handle specialist work that would normally trigger safeguards on Anthropic’s public models.
Claude Mythos 5.1 costs $10 per million input tokens and $50 per million output tokens. It has a one-million-token context window and can return up to 128,000 tokens in one response.
You cannot select Mythos 5.1 through a Free, Pro, Max, or Team subscription. Anthropic grants access through trusted programmes for vetted organisations, and it currently limits that access to selected organisations in the United States.
This guide covers the model’s price, features, availability, access rules, and how it differs from Claude Fable 5.1.
It is Anthropic’s restricted AI model for vetted cybersecurity and life science organisations. It replaces Claude Mythos 5 and gives you the same general coding, research, and knowledge work skills as Claude Fable 5.1.
Mythos 5.1 and Fable 5.1 use the same underlying model, but the two versions carry different access rules and safeguards. Mythos uses more permissive controls for approved professional work in cybersecurity and biology, while Anthropic’s other safety rules stay in place.
The model accepts text and images and returns text. It can analyse source code, research files, screenshots, tables and document pages. Adaptive thinking stays on at all times, and an effort setting controls how much reasoning it uses.
Anthropic introduced Claude Mythos Preview through Project Glasswing on April 7, 2026. Selected technology organisations used it to find weaknesses in important software systems and recommend defensive fixes.
Anthropic committed $100 million in usage credits to the early project. The company listed a post-credit price of $25 per million input tokens and $125 per million output tokens for Mythos Preview.
Anthropic expanded Project Glasswing to about 150 more organisations across more than 15 countries on June 2. It then released Claude Mythos 5 on June 9 at a lower price of $10 for input and $50 for output per million tokens.
Export control questions disrupted Mythos 5 access shortly after launch. Anthropic said on July 1 that US government approval let it restore access for a group of US organisations.
It launched on September 1, 2026. It replaced Mythos 5 as Anthropic’s newest specialist model for approved cyber defenders and life scientists.
Older articles may still show the Mythos Preview price of $25 for input and $125 for output. The current Mythos 5.1 prices are $10 and $50 per million tokens.
Anthropic charges you for the amount of text and reasoning the model processes. Your final cost depends on the prompt, the response, and how much effort and caching you use.
Prompt caching lets an organisation store information the model will reuse, like a large code repository, research documents, or tool instructions. Each cache read costs $0.25 per million tokens.
Mythos 5 charged $1 per million cache read tokens. Mythos 5.1 cuts that amount by 75%. Cache writes stay at $12.50 for five minutes and $20 for one hour.
Batch processing costs half the normal input and output rates. It suits work that does not need an immediate response.
Claude subscriptions do not give you normal Mythos 5.1 access. Free, Pro, Max and Team users cannot choose it from the standard model selector.
Your organisation must receive approval through an Anthropic trusted access programme, plus separate API or cloud platform billing. Approval does not remove usage charges.
Mythos 5.1 supports approved defensive cybersecurity research. It can help vetted teams identify weaknesses in source code, examine software in controlled environments, and suggest fixes for human review.
Anthropic limits access because the same technical skills could be misused. The trusted programmes require organisations to use the model only for authorised, defensive work.
The model supports advanced biology and life science research for approved professionals. Anthropic says its Life Sciences Verification Program uses safeguards built for legitimate professional research and development.
Mythos 5.1 can continue across long sequences of research, tool calls, and revisions. It can update you on its progress and recover from some problems without restarting the task.
The model can work across large code repositories, write tests, and review proposed changes. Anthropic’s Claude Security product now uses Mythos 5.1 to scan codebases and suggest patches for people to review.
Mythos 5.1 shares Fable 5.1’s ability to complete multistep research and produce reports, spreadsheets, documents, and presentations. It can combine text and visual information from large collections of files.
Developers can select an effort level for each message. Higher effort gives the model more room to reason through difficult tasks, though it also uses more tokens and can add to latency. The default effort level is high.
A one-million-token context window can hold a large collection of source code or research documents. It does not guarantee perfect recall across every part of the input, so test the model with your own material before you use it in production.
It is currently unavailable to Nigerian organisations. Anthropic says it currently provides the model to a set of approved US organisations.
Project Glasswing previously expanded Mythos Preview to organisations in more than 15 countries, but that earlier expansion does not confirm current Mythos 5.1 access in those countries.
You can still access Claude Fable 5.1 through eligible paid plans or Anthropic’s commercial API from Nigeria. You cannot select Mythos 5.1 through a regular Claude account.
Anthropic says it plans to expand its trusted access programmes, though it has not published a date for Mythos 5.1 access in Nigeria or another African country.
Anthropic’s Life Sciences Verification Program is an invite-only beta for advanced life science organisations. Anthropic built the programme with the US government and has enrolled its first participants.
The Cyber Verification Program gives approved defenders access to selected Claude models with reduced cybersecurity safeguards. Anthropic says Mythos-class access will join this programme soon, though it has not announced a full rollout date.
Project Glasswing is Anthropic’s programme for organisations that build or protect important software systems. Approved partners use Mythos models for authorised defensive security work.
Organisations seeking approved access can contact their Anthropic, Amazon Web Services or Google Cloud account team. Anthropic reviews the organisation and intended use before it grants access to the model.
Anthropic lists four supported platforms:
A normal account on any of these platforms does not give you automatic access. Anthropic has to approve your organisation first.
Their general intelligence and specifications match. Mythos can complete some specialist cybersecurity and biology work that Fable may stop or send to an Opus fallback model. Fable stays the version built for general users.
Mythos 5.1 keeps the standard $10 input and $50 output prices from Mythos 5. Its cache read price falls from $1 to $0.25 per million tokens.
The new version also adds or improves:
If you are moving from Mythos 5, review several API changes first. Forced tool use is not supported, and earlier models cannot read Mythos 5.1 thinking blocks. Changes to earlier conversation content can also affect preserved reasoning, though Anthropic says Mythos does not run Fable 5.1’s strict prefix integrity check.
Opus 5 costs half as much at standard API rates and runs with lower latency. It suits general reasoning and production work. Mythos 5.1 is built for approved organisations whose specialist research needs its trusted access safeguards.
True scale demands moving beyond surface-level integrations to robust execution. We’ve filtered the noise out of Moonshot 2026, optimising the conference strictly for high-calibre connections between startup founders, global financial operators, enterprise leaders and individuals rewiring Africa’s technical frameworks. Get 20% off Early Bird tickets for a limited time.
Follow the story
