(This was originally going to be a "quick take" but then it got a bit long. Just FYI.)

There's this weird trend I perceive with the personas of LLM assistants over time. It feels like they're getting less "coherent" in a certain sense, even as the models get more capable.

When I read samples from older chat-tuned models, it's striking how "mode-collapsed" they feel relative to recent models like Claude Opus 4.6 or GPT-5.4.[1]

This is most straightforwardly obvious when it comes to textual style and structure: outputs from older models feel more templated and generic, with less variability in sentence/paragraph length, and have a tendency to feel as though they were written by someone who's "merely going through the motions" of conversation rather than deeply engaging with the material. There are a lot fewer of the sudden pivots you'll often see with recent models, the "wait"s and "a-ha"s and "actually, I want to try something completely different"s.[2]

And I think this generalizes beyond mere style: there's a similar quality to the personality I see in the outputs. The older models can display a surprising behavioral range (relative to naive expectations based on default-assistant-basin behavior), but even across that [...]

The original text contained 7 footnotes which were omitted from this narration.

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First published:
April 28th, 2026

Source:
https://www.lesswrong.com/posts/f5DKLsTsRRhbipH4r/llm-assistant-personas-seem-increasingly-incoherent-some

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Narrated by TYPE III AUDIO.