$ [sudo] pip install gist-description

$ [sudo] npm i -g gist-description

$ export GITHUB_TOKEN="<GITHUB_TOKEN>"

$ gist-description <id> "new description"
$ gist-description <id>
new description

$ pip install gist-id

find ~/git/gists -type d -maxdepth 1 -exec bash -l -c 'id=$(gist-id "$0"); desc="$(basename "$0")"; [[ -n $id ]] && gist-description $id $desc' {} \;

$ find ~/git/gists -type d -maxdepth 1 -exec bash -l -c 'id=$(gist-id "$0"); desc="$(cat description.txt 2> /dev/null)"; [[ -n $id ]] && [[ -n $desc ]] && gist-description $id $desc' {} \;