Now that I've dug my hands deep into the Mastodon core, it looks like it's definitely possible to get the original home instance counts for federated posts, not just your own server's local tally.

For boosts and favourites, recent versions of Mastodon already fetch the origin's reported totals when retrieving a post and store them as "untrusted counts" (untrusted because the remote server self-reports them). So a remote post carries the home server's actual numbers.

Replies are trickier, as they only federate to subscribed servers, so the local count tends to lag. However, you can fetch the full reply tree from the origin on demand.

I'm basing our algorithmic home feed exactly on that: boosts and favourites from the origin counts, and comments from a backfilled reply tree.

Add opt-in ranked home timeline (experimental)
#4
https://github.com/mementomori-social/mastodon/pull/4

The numbers in question have been requested for ages:

Boosts and favourites counts #22627
https://github.com/mastodon/mastodon/discussions/22627

Show the number of reshares, likes, and comments directly in the timeline
#8280
https://github.com/mastodon/mastodon/issues/8280

#MastoAdmin #OpenSource #Mastodon #FYP