Spec checks
How the Spice++ assistant measures your targets from a simulation, reports the margin, repairs a design that misses, and cross-checks with ngspice.
When you give a target, the assistant measures it from a simulation and shows a table: the spec, the target, the measured value and the margin between them, with the overall result above it.
A failed row means the design missed; the assistant can then diagnose and repair it, and checks again.
A second opinion
Any run can also be repeated in ngspice, an independent SPICE engine running in the same tab. When the two cannot be compared fairly, the result says so instead of reporting a match.