Claude 5 (Fable 5 / Opus 5 / Sonnet 5) ☆

Anthropic opened its Claude 5 generation with Fable 5 (announced June 9, 2026): a new frontier tier above Opus with always-on adaptive thinking, a 1-million-token context window and 128K output tokens. Sonnet 5 followed on June 30 for agentic coding and knowledge work, and Opus 5 on July 24 — positioned as approaching Fable 5's intelligence at half the price, and the new default on the Max plan — Anthropic's fourth Claude 5 release in under two months. A restricted Mythos-class variant (Claude Mythos 5) shares Fable's underlying model and is available only to approved organizations. Parameters undisclosed.