analyze-nsys-profile
Query a captured PithTrain Nsight Systems profile to measure compute/communication overlap, locate exposed comm by DualPipeV stage, and inspect per-rank stream behavior. Use when the user asks to "analyze an nsys profile", "check overlap quality", "find exposed comm", "which stage is the bottleneck", or any question that starts from an existing `.nsys-rep` file. Assumes the trace was already captured (see capture-nsys-profile); provides query primitives the agent composes for the specific question being asked.