@crepels @FenTiger I spent *way* too long trying to figure out how to get my library (https://github.com/jahfer/clj-activitypub) to talk to Threads. Thank you! Your post was the thing that helped me to pull an actor document.
Being stubborn, I tried to get to the bottom of why the instance actor stuff was required. Turns out...it's not! Threads just requires that the signing actor has a `url` field, which isn't common except for the instance actor. How anticlimactic 😑 I'm going to flag this to the Threads folks.