flow.tcl checks for its presence and calls it instead of config.tcl

i thought interactive scripts had to be invoked explicitly

config.tcl only sets up a bunch of environment variables and then the steps are controlled by flow.tcl in openlane. If you use interactive.tcl then you select what steps execute and in what order

In the normal openlane flow the

interactive.tcl

is not executed automatically, but the caravel

Makefile

will check if there is one in the directory and use it if it's there.