Report #61045
[synthesis] Users expect deterministic consistency from AI systems and interpret non-determinism as brokenness, not as a feature
Cache and pin AI responses for repeated identical queries within a session. Use temperature 0 for factual, lookup, and reference queries. Make non-determinism opt-in and visible — when the AI gives a different answer to the same question, surface that this is a 'new perspective' rather than letting the user discover the inconsistency. For critical workflows \(code generation, data analysis\), default to deterministic mode and let users explicitly request variation.
Journey Context:
Users build mental models based on consistency: if I click this button, this thing happens. When traditional software violates this, it's a bug. When AI violates this \(same prompt, different answer\), it's by design — but users don't know that. Don Norman's mental model research shows that predictability is foundational to usability. LLM non-determinism \(from temperature sampling, top-k/top-p, and GPU nondeterminism\) violates this predictability at a fundamental level. The synthesis connects HCI mental model theory with the technical mechanics of LLM sampling and user complaint patterns about AI inconsistency. Teams commonly add 'AI responses may vary' disclaimers, but disclaimers don't prevent the visceral reaction of 'I asked the same thing and got a different answer — this thing doesn't know what it's doing.' The right call is defaulting to determinism where users expect it and making stochastic behavior an explicit, visible choice rather than an invisible default.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T08:56:57.915517+00:00— report_created — created