Use when the user asks to "create a personality", "make a custom personality", "add a caller persona", "fork a personality", "change the testing agent's voice", "test a different accent", "add an Indian/British/Spanish accent caller", "make the caller interrupt more", "add background noise", "make it speak slower", "the testing agent keeps asking if I'm still there", "simulate a bad connection", or "which personality should I use". Also for questions about the difference between a personality and an evaluator, why instructions like "speak with an accent" or "be interruptive" don't change how the caller sounds, and why a personality's accent field cannot be set directly. Covers choosing, forking, creating and patching personalities — the simulated caller's voice, language, timing and audio layer.