Original, source-checked analysis of how often and how long ChatGPT, Codex, Claude and Gemini have problems, built from public status pages, incident write-ups and our own published datasets. We count incidents, measure how long they stay open, check whether status-page times match the providers’ own write-ups, rebuild the uptime figures the pages publish, and say plainly what the data cannot show. Every article links to its data and states its limits. Start with the State of AI Reliability overview, then read the guides on status-page stages, uptime, and outage write-ups.