Hi Bram,
We are in the process of retiring puppet-client-tools entirely. Shipping puppet-client-tools was significant overhead for a package that only contained the PuppetDB CLI. Also, in an effort to limit the number of languages we develop in, we have rewritten the PuppetDB CLI in Ruby and released it as a gem.
On a machine running puppet 6 I recommend installing the PuppetDB CLI via one of the following commands (depending on which scope you've installed Puppet in), and ensure whichever path you use for --bindir is also added to your shell's PATH.
For Puppet installed in its system location
gem install --bindir /opt/puppetlabs/bin puppetdb_cli
For Puppet installed for the current user
gem install --bindir ~/.puppetlabs/bin puppetdb_cli
If the machine is not managed by Puppet, it is also possible to install to your default Ruby bindir (by omitting the --bindir option entirely) and use via the puppet-query and puppet-db commands directly.
gem install puppetdb_cli
The documentation for installing puppet-client-tools will be updated shortly with the new gem installation steps. If you have any problems with the new PuppetDB CLI please file a PDB ticket in Jira so we can get it fixed.