Fable 5, Anthropic’s new Mythos-class model, launched on the AI/ML API (announced…

Brief

Fable 5, Anthropic’s new Mythos-class model, launched on the AI/ML API (announced 2026-06-09) with a 1M-token context window and pricing of $10/1M input and $50/1M output. The poster ran Opus 4.8 vs Fable 5 on a 3D Pokémon task, praising Fable 5’s speed and SOTA strength on long, complex tasks while acknowledging Opus remains useful; Anthropic says Fable 5 is safe for general use.

Fable 5, first Mythos-class model is live on AI/ML API!

We ran a fun test: Opus 4.8 vs Fable 5 are generating a 3D Pokemon.
Verdict? Fable 5 is brilliant, fast, and rare as Mew… but Opus is still that nice little guy who does great stuff. 💛

Fable 5 Important bits:

SOTA on nearly every benchmark, and the lead only grows on longer, complex tasks.

• 1M Context
• $10 / 1M input
• $50 / 1M output

Built for: long-horizon agentic coding, big migrations, vision-to-code, deep research.

Video

Claude (@claudeai)

Introducing Claude Fable 5: a Mythos-class model that we’ve made safe for general use.

Its capabilities exceed those of any model we’ve ever made generally available.

Video

— https://nitter.net/claudeai/status/2064394146916229443#m