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Anthropic’s launch of a version of its artificial intelligence model that it previously claimed was too powerful to release has garnered excitement as well as criticism over the cost.
Called Fable 5, which some are calling “Mythos Lite”, it is included in the Claude subscription but only until June 22. Users will then have to pay full price, which some online have said is too expensive.
“A few prompts just to test it out and it ate 5% of my monthly allowance… I have no reason to use this without a trust fund,” one user on Reddit wrote.
Released on June 9, 2026, Fable 5 gives general users access to what Anthropic calls “Mythos-level” capability but with a built-in safety trigger that shuts down the model and reverts to the older Claude Opus 4.8 if they ask about high-risk topics such as cybersecurity, biology, chemistry or distillation.
In April, Anthropic announced its Mythos model, which it said was too powerful for public launch because it is too effective at finding high-severity vulnerabilities, or potential weaknesses, in major operating systems and web browsers.
How much does Fable cost?
Anthropic says Fable costs $10 or approximately €9 per million input tokens and $50 per million output tokens. Put into context, it is double the price of the company’s previously most expensive model, Claude Opus 4.8.
Tokens are units of data that are processed by AI. A token can be a word, a punctuation mark, blank space, pixels in an image or even a blank space. It is estimated that in English, one token is around four characters or 75% of a word. So 1,000 tokens is considered to make up 750 words.
Fable requires more compute and tokens as it can exercise more complex tasks, the company says. Fable can run multiple AI agents and work autonomously for days.
“Fable 5 has the highest score of any model, with substantial gains in document-based reasoning, chart and table interpretation, and problem solving,” Anthropic said.
It can also extract precise numbers from detailed scientific figures and perform complex vision-based tasks such as rebuilding a web app’s source code from screenshots.
Still, whether that justifies the price is another matter as companies become more aware of the costs of AI.
In comparison to rival OpenAI’s model GPT-5.5, Fable is more expensive than the standard GPT-5.5, which is $5 per million input tokens and $30 per million output tokens.
But Fable is cheaper than OpenAI’s pro version of the GPT-5.5 model.
The AI model cost is heating up between companies, with OpenAI reportedly considering cutting prices for paid access to its AI models, the Wall Street Journal reported on Wednesday, citing sources familiar with the matter.
The companies are also competing on valuation, with OpenAI this week confidently filing for an initial public offering with the US Securities and Exchange Commission.
It comes shortly after Anthropic made the same move last week.