How do you build content moderation / toxicity classification, and what makes it hard?

Toxicity detection looks like plain text classification but is nothing of the sort: context flips labels, adversaries evolve weekly, and naive models tag dialects as hate. The signal is naming those failure modes and building the human-in-the-loop system around them.

Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.