ANTHROPIC
Launched with one hand on the panic button
Claude has launched Fable 5, its most powerful generally available model yet, built for coding, research, vision, knowledge work and longer, more complex tasks.
The company says Fable 5 outperforms its previous models across most major benchmarks, especially on work that needs deeper reasoning and more context.
Early testers reported strong results too, including Stripe saying the model handled a major codebase migration in one day instead of more than two months. Casual.
But a model this powerful also comes with obvious risks.
To reduce misuse, Claude has added stricter safeguards around areas such as cybersecurity, biology and chemistry.
If Fable 5 detects a higher-risk request, it will hand the response over to Claude Opus 4.8 instead.
Claude says this fallback happens in fewer than 5% of sessions on average, though some harmless requests may still get caught.
Claude is also launching Mythos 5, which uses the same underlying model as Fable 5 but with some safeguards lifted for approved users.
For now, access is limited to cyber defenders, infrastructure providers and, later, selected life sciences researchers through trusted programmes.
The model also shows promise in science.
Claude says Mythos 5 helped speed up parts of drug design by around ten times and produced molecular biology hypotheses that researchers preferred over previous Opus-class models in blind tests.
The main bits:
Fable 5 is Claude’s strongest public model so far, with better coding, vision, reasoning and long-context skills.
Some risky prompts will fall back to Opus 4.8, because apparently “very smart model with cyber skills” needs a seatbelt.
Mythos 5 is the same base model with fewer restrictions, but only for approved cyber and research partners.
Mythos stays invite-only
Both models cost $10 per million input tokens and $50 per million output tokens.
Fable 5 is available through the Claude API, while subscription users on Pro, Max, Team and seat-based Enterprise plans get included access until June 22.
After June 23, usage credits will be required unless Claude extends the free access window.
Anthropic built the AI equivalent of a gifted child, then immediately told it not to touch the chemistry set. - MG