Claude: Degraded Performance for Multiple Models

Multiple Claude models, including Opus 5, Mythos 5, Fable 5, Sonnet 5, Haiku 4.5, and others, experienced degraded performance from 16:11 to 18:23 UTC on August 18 2026. The issue was investigated, a fix was applied for Opus 5, and results are being monitored. Updates will be posted as further information becomes available.