but for some reason, thunderbird keeps asking me for password. I have checked /run/agenix.d/1/microsoft and it contains the password. I’m not sure what I’m doing wrong here.
passwordCommand is for the various fetcher services, Thunderbird has no way of using it. I somewhat doubt it supports any of the email account settings, actually. I think Thunderbird supports the secret service, though, so you can hook something like the gnome keyring or keepass to it.
But the module does not use passwordCommand. I’d assume this is because Thunderbird has no way to execute a shell command for authentication, which isn’t really expected from a glossy GUI client.