Claude change history: Elevated errors for Claude Sonnet 5

Claude Sonnet 5 requests experienced elevated errors across claude.ai, Claude API (api.anthropic.com), Claude Code and Claude Cowork in a major-impact incident starting 2026-09-03 12:37 UTC. A fix was implemented by 12:47 UTC; the incident was resolved at 2026-09-03 12:56 UTC, with a reported duration of 18 min.