Anthropic tests Fable 5.2 and Opus 5.5 ahead of the release

It seems that Anthropic has begun quietly testing its upcoming frontier model in the wild. Some early examples of what appears to be Claude Fable 5.2 appeared on X this weekend, just a few weeks after Anthropic had launched Claude Fable 5.1. Before diving into the details, it's worth noting that users who shared the alleged outputs said the standard prompts they usually received were now generating responses that seemed much more advanced than anything Claude typically produces. Anthropic hasn't commented on the potential A/B test yet.

Also reported by TechCrunch.

First reported by TestingCatalog. This page is a short excerpt; the full text is theirs.