Anthropic change history: Elevated errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5

Anthropic reported a major incident with elevated request errors for Claude Mythos 5, Claude Fable 5, and Claude Sonnet 5, affecting claude.ai, Claude API (api.anthropic.com), Claude Code, and Claude Cowork. It started at 2026-08-13 14:33 UTC and was resolved at 2026-08-13 16:08 UTC, lasting 1 h 34 min; no cause or fix was stated.