What smart people are saying about the 2 most controversial parts of Anthropic's new models

• Anthropic unveiled Claude Fable 5 and Mythos 5, its long-awaited “Mythos-class” AI models.
• The company said the models include safeguards that limit some frontier AI research tasks.
• Critics said the restrictions blur the line between AI safety measures and competitive strategy.

“Mythos will be bad ON PURPOSE on AI ‘frontier LLM research’ tasks,” Bakouch wrote on X on Tuesday. “This is very very sad for the research community.”

Bakouch also called it “crazy” that the intervention would not be visible to users.

Jeremy Howard, cofounder of AnswerDotAI

Jeremy Howard said that Anthropic’s safeguards could increase concentration in the AI industry.

“Anthropic has chosen the opposite of the safe path,” Howard wrote in an X post on Wednesday. “They are allowing themselves, the current top lab, to use their top model for frontier AI research.”

Howard said the result is that “the AI frontier advances, & power imbalance increases.”

Patrick Moorhead, founder and CEO of Moor Insights & Strategy

Patrick Moorhead said his first experience with Fable 5 left him underwhelmed.

In a post on X on Wednesday, Moorhead said the model refused to help with earnings-analysis talking points and a board presentation because Fable 5 deemed the tasks “too dangerous.”

“Is this the model we’re all frightened of and makes Anthropic worth $1T?” he wrote. “Okedokee.”

Gergely Orosz, author of ‘The Pragmatic Engineer’ newsletter

Gergely Orosz said Anthropic’s safeguards could end up affecting people who aren’t actually building competing AI models.

“Anthropic assumes SemiAnalysis is developing a competing LLM and so it dumbs down their model for them,” Orosz wrote on X on Wednesday.

“Anthropic trying to limit competition limits many others,” he added.

Deedy Das, partner at Menlo Ventures

Deedy Das focused on the model’s capabilities rather than its safeguards.

“Claude Fable 5 is by far the most ridiculous model that makes me genuinely afraid for the future of software engineering,” Das wrote in an X post on Wednesday.

Das pointed to examples including migrating a 50 million-line codebase, generating advanced 3D graphics, and outperforming rival models on optimization tasks.

He also said that Fable 5 is about the same price as OpenAI’s GPT-5.5 and six times cheaper than GPT-5.5 Pro.