Fable 5 is here. The benchmark flex is real — the moat isn't.

Here's what happened on 9 June: Anthropic opened the gates on its Mythos tier with Fable 5, a model it says beats Opus 4.8 by 10%+ on some benchmarks and works autonomously for longer than anything before it. Good. Genuinely good.

Now the part the launch post soft-pedals. The same Mythos lineage that makes Fable 5 special is the lineage that spooked the government over cyber-vulnerability hunting — so Anthropic fenced the model off in cybersecurity, biology, chemistry and distillation, where it just refuses and hands you Opus 4.8 instead. The most powerful model is the one you're least allowed to point at the hard problems.

Free until 22 June, then $10/$50 per million tokens — about double Opus. Anthropic even says paid-plan access only comes back 'when capacity is sufficient.' Translation: this is expensive to run, supply is tight, and you'll pay frontier rates for it. That's not a moat. That's a meter.

Anthropic's own defence, days later, gave the game away: pushing back on a government recall, it argued that competitors share the same capability — pointing at OpenAI's GPT-5.5. You can't simultaneously hold that the dangerous strength is unique enough to fence off and common enough that banning yours is pointless. Pick one. The market already did: capability converges, price competes, and the lead measured in a June benchmark rarely survives to Christmas.