Saturday, 30th August 2025
LLMs are intelligence without agency—what we might call "vox sine persona": voice without person. Not the voice of someone, not even the collective voice of many someones, but a voice emanating from no one at all.
Claude Opus 4.1 and Opus 4 degraded quality. Notable because often when people complain of degraded model quality it turns out to be unfounded - Anthropic in the past have emphasized that they don't change the model weights after releasing them without changing the version number.
In this case a botched upgrade of their inference stack cause a genuine model degradation for 56.5 hours:
From 17:30 UTC on Aug 25th to 02:00 UTC on Aug 28th, Claude Opus 4.1 experienced a degradation in quality for some requests. Users may have seen lower intelligence, malformed responses or issues with tool calling in Claude Code.
This was caused by a rollout of our inference stack, which we have since rolled back for Claude Opus 4.1. [...]
We’ve also discovered that Claude Opus 4.0 has been affected by the same issue and we are in the process of rolling it back.