Ansible's default output, including the
stderr of failed commands, is JSON
encoded, which makes reading Jenkins' output hard.
Ansible however has Callback plugins that could be used. In that page it says:
Ansible comes with a number of callback plugins that you can look at for examples. These can be found in lib/ansible/plugins/callback.
That is a link to a git repo with just a pile of Python sources and no, say
README.md index to what they do. Hopefully they have some docstring with a short description of what they do?