Anthropic Internal Docs Reveal Opus 5 Progress

Internal Anthropic materials indicate Claude Opus 5 is only slightly better than Mythos 5, though a follow-up suggests version 5.1 has already been usable for some time.

2026-07-25 ~ 2026-07-25 · 2 related posts

• Anthropic memo says Claude Opus 5 may be only a small step up over Mythos 5 — RyanGreenblatt · 2026-07-25
• Reply says version 5.1 has been available for a while — zephyr_z9 · 2026-07-25