ChatGPT, Claude, Grok and Gemini all showed problems during the same Thursday-morning window, with no shared cause established. Anthropic reported elevated errors beginning at 9:23 a.m. Eastern on Thursday. Anthropic marked the main incident resolved at 12:16 p.m.
The documented sequence in “Four Frontier AI Services Suffer Overlapping Interruptions” adds several concrete details. OpenAI reported degraded ChatGPT and Codex performance at 10:43 a.m. OpenAI marked its incident resolved at 12:55 p.m. Grok displayed a user-facing service issue message.
The supporting record also establishes the following. Monitoring services recorded a shorter Gemini disruption. The four services are operated by separate companies.
The relevant background is narrower than the headline alone may suggest. AWS, Azure and Cloudflare did not report matching major incidents. Overlapping timing does not by itself prove a common cause. Sources are identified below so that the underlying report and any attributed institutional statement remain visible to readers.
The evidence available by the edition deadline has a defined boundary. Providers had not published detailed postmortems, and Google had not publicly confirmed its event in the checked report. The next documented updates are expected to address provider postmortems and dependency disclosures and whether monitoring data reveal a shared upstream service.
For a complete dated record, the verified points retained for “Four Frontier AI Services Suffer Overlapping Interruptions” are: Anthropic reported elevated errors beginning at 9:23 a.m. Eastern on Thursday. Anthropic marked the main incident resolved at 12:16 p.m. OpenAI reported degraded ChatGPT and Codex performance at 10:43 a.m. OpenAI marked its incident resolved at 12:55 p.m. Grok displayed a user-facing service issue message. Monitoring services recorded a shorter Gemini disruption. The contextual record is: The four services are operated by separate companies. AWS, Azure and Cloudflare did not report matching major incidents. Overlapping timing does not by itself prove a common cause. This account distinguishes reported events from unresolved claims and does not extend beyond the cited material.