@Mariana Huerta Tried annotating vth in a schematic and it works.

I haven't been able to get the vth annotation to work yet, I followed your previous steps adding .control/save/.endc to my netlist and adding this line to the annotation symbol. Am I missing something?

when simulation is done you need to annotate the data into the xschem schematic. This is done by issuing this command into the xschem prompt:

ngspice::annotate

Also note that only operating point data is annotated, so your simulation must be a

.op

there is a

sky130_tests/test_analog.sch

schematic that shows how annotation works. There are many comments in the schematic.

I will take a look, thank you so much!