@User backannotation devices are ordinary symbols like

spice_probe.sym

,

ammeter.sym

,

ngspice_probe.sym

,

ngspice_get_value.sym

,

ngspice_get_expr.sym

. See example in

sky130_tests/test_analog.sym

. Once these components are placed / attached to the circuit and .op operating point ran and saved, backannotation is done by executing the command:

ngspice::annotate

. I usually place a '`launcher.sym`' component in the schematic. This is a symbol with a '`tclcommand="ngspice::annotate`" attribute. If you ctrl-Button 1 mouse click on it backannotation is done. Doing this automatically means binding the '`ngspice::annotate`' command to some events, like a file load or a simulation run. I personally prefer to update backannotation data manually. May be i can add some attribute globally in the schematic properties, like '`annotate_auto_update=true`' or similar to trigger this automatic update. The goal is to avoid multiple useless updates, if no new data is generated (no new simulation) for efficiency reasons.