I already told you my app is LIBPQ aware, including about PGPASSWORD and PGSERVICE.It's users who decide to use these mechanisms (which have plain-text passwords BTW...), not my tool.The same way PSQL prompts for a password when not using these mechanism, so does my tool.
Once you have the password you should utilize the PGPASSWORD environment variable to get it passed to psql. It doesn’t matter in the least how you obtained that password in the first place.
David J.