Nobody Touched the Code - Reliability engineering for non-deterministic software

One line disappeared from a system prompt during an ordinary week of edits. The tests stayed green. The JSON stayed valid. And the classifier quietly began routing almost every request to the wrong specialist — a production failure nobody caused by touching the code. This evening is about the failures that look correct: behavioural drift in LLM systems. Output that a human reader would sign off on, that passes every schema check, and that safe fallbacks quietly paper over — so a mis-routed request can go unnoticed for days. We'll look at why the usual answers (add validation, write more evals) don't catch it, and what testing, observability, and plain engineering discipline actually look like when your software is non-deterministic. Then we open it up: a panel on who owns reliability when the code didn't change — system prompts as code vs. config vs. content, safe fallbacks vs. loud failures, and whether an LLM feature can ever earn the same trust as deterministic code. Developers and architects running LLM features in production, or about to — this one's for you. Schedule 18:00 — Doors, drinks & networking 18:30 — Welcome & housekeeping 18:35 — Talk "Behavioral drift: the silent bugs in LLM workflows" + Q&A 19:15 — Short break 19:25 — Panel discussion - TBD - TBD - TBD 20:05 — Open networking ~21:00 — Wrap Details 📅 Tuesday, 6 October 2026 🕕 18:00 🗣️ Language: English 🎓 Level: Intermediate — developers and architects