I've made a site_facts module that adds some facts I use in my
playbooks. I'm also using tags to sometimes run subsets of my
playbooks, which I believe is the primary motivation for tags. My
problem comes in when I want to use some of the facts added by my
site_facts module when running only a subset of my tasks. For
example:
I have a similar issue, though not totaaly related. The extra facts are things I can calculate ofline (primarily network information, ip addresses, based on a preconfigured vlan), without touching the hosts first. I hope to solve this with an inventory plugin.