<objective AI features fail differently from deterministic software. The same input produces different outputs, correctness is subjective, and failure modes include hallucination, prompt injection, and silent quality decay. A chatbot that confidently cites a fabricated URL passes every check. This skill covers how to test AI features rigorously despite nondeterminism: versioned prompts, eval suites scored against golden datasets, statistical and property-based assertions, tool-call validation, grounding checks, and red-team safety scans. </objective --- Quick Route | Situation | Go to | |----…