Are auto-regressive LLMs deterministic?

Yes in theory, which was my intuition and understanding. It’s less true in practice though, and Perplexity summarized this very well:

https://www.perplexity.ai/search/Theoretically-is-a-qr0ecAieSrKlXcCiWGzGwQ

I’ve seen this come up more than once, most recently in a community slack today, which prompted this brief sidetrack.