Sometimes a date is the whole story. Today, June 22, is the last day of the free window for Claude Fable 5 — the safeguarded Mythos-class flagship Anthropic shipped on June 9. If you have Pro, Max, Team, or a seat-based Enterprise plan, you got to use the model for about two weeks at no extra cost. Starting tomorrow, that’s over.
What changes on June 23
From June 23, Fable 5 drops out of the normal plan limits. If you want to keep using it, you pay through usage credits — at full API rates. And those rates are steep: roughly $10 per million input tokens and $50 per million output tokens. That’s about double Opus 4.8, making Fable 5 the most expensive generally available model Anthropic ships. Batch work and prompt caching bring the cost down — but the jump from “free” to “premium tier” is hard to miss.
The free window was pretty clearly meant to be exactly what it was: a generous taste. Anthropic lets you try the strongest tool in the box, and once you’ve grown used to it, the bill arrives.
A model with a turbulent history
Fable 5 packed more drama into its first two weeks than some models see in a lifetime. Shortly after launch, Anthropic had to shut access off entirely on June 12 in response to a US government export-control directive. The model only came back around June 18 — this time with mandatory identity verification and nationality-based geo-fencing that didn’t exist before. So if you’re grabbing one last free day with Fable 5 today, you’re using a model that’s already been on a small odyssey.
My take
I think the free-trial model is fundamentally fair — you get to test whether the Mythos class is worth the premium before you pay for it. The honest question is just: is it? For most tasks, Opus 4.8 is strong enough, and at half the price. Fable 5 earns its keep where the last few percent of capability genuinely matter — complex software projects, demanding knowledge work, vision. My tip: run a couple of real tasks through it today, the kind you’d normally hand to Opus. By tomorrow you’ll know whether you need the credits — or whether you can happily stick with Opus.
Sources: Anthropic: Claude Fable 5 and Claude Mythos 5, Simon Willison: Initial impressions of Claude Fable 5