Anthropic launched Claude Fable 5, its most capable consumer-facing AI model to date, but with a catch: some sensitive cybersecurity requests are automatically downgraded to a less powerful model.
The company said Fable 5 excels at coding, research and other knowledge-intensive tasks, particularly over long and complex workloads.
To curb potential abuse, Anthropic built in guardrails that redirect certain high-risk queries to Claude Opus 4.8. The filters activate in fewer than 5% of sessions on average, according to the company.
Mythos 5 uses the same underlying model as Fable 5 but drops some of the restrictions—for a select group of cyber defenders, critical infrastructure operators and other trusted partners.
The company said Mythos 5 will first be delivered through Project Glasswing in partnership with the U.S. government as an upgrade from Claude Mythos Preview, with broader access planned through a trusted program.
