You can now get completion for cf-* commands if you are using Bash and bash-completion helper
Simply put contrib/cfengine-completion.bash into your bash_completion.d directory:
# wget https://raw.github.com/cfengine/core/master/contrib/cfengine-completion.bash -O -|sudo tee /etc/bash_completion.d/cfengine
Restart your shell, and enjoy:
$ cf-promises --<tab><tab>
--bundlesequence --diagnostic --full-check --negate --verbose
--debug --dry-run --help --policy-output-format --version
--define --file --inform --reports
$ ~/.cfagent/bin/cf-promises --bundl<tab>
$ ~/.cfagent/bin/cf-promises --bundlesequence