If the update is:
set -e -u -o pipefail
(dos-make-addr-conf | tee config.toml) && dosctr set template_vars config.toml
well....
`tee config.toml` will still produce a empty config.toml
(set -e - u -o pipefail;false | tee config.toml) && cat config.toml
But you can use the '>' operator, that will create the file only if the command runs successful:
dos-make-addr-conf > config.toml && dosctr set template_vars config.toml