Anthropic’s artificial intelligence models, such as Claude Mythos 5.1, Claude Fable 5.1 and Claude Opus 5, registered high errors in their requests on the afternoon of September 3, 2026. The instability is under investigation by the company, directly impacting users and developers who depend on these AIs for their activities.

Which Claude systems are at fault

The affected systems are advanced versions of Anthropic’s AI, used in a variety of applications, from writing to data analysis. High errors mean that user requests are not being processed correctly, disrupting workflow and productivity.

Recurrence of instabilities in Claude services

This is not the first time that the platform has faced problems, signaling a possible recurrence of instabilities. In recent weeks, Anthropic has reported failures in other models, such as the Claude Sonnet 5 (on September 2 and 3, 2026) and even the Mythos 5, Fable 5 and Opus 5 (on August 24, 2026). This frequency raises concerns about the long-term reliability of AI services. The company monitors the situation to restore normality.