Rogir:Actually, there are some people who would use 'far' instead of 'de' to indicate the agent in a passive construction. Especially on Facebook it's quite common.

Surely that's in combination with, as opposed to instead of? Like "rompiĝis far de.." ?

tommjames:I don't know a great deal about "fare" but I've been advised it can work in this way, and it would seem to make the point about passivity quite well. Do you think it works ok?

Personally, no. I don't know what you would mean by that.

"La branĉo estis rompita". I don't like it but it does seem that it is by far the most common way of showing the action, despite its obvious confusability with the state of having been broken.

I think you are making a big deal out of this

Ιf you really need to specify a certain quality or feature that would otherwise be too unclear or could be overlooked, you should express it openly. If something gets broken by itself, just say that it got broken by itself. If something was broken when you found it, but it is not broken now, just say that. I understand (and usually encourage) the attempt to find a more elegant, less verbose way to express the same meaning, but if you seriously aim for clarity, and fewer words would compromise it (for one reason or another), then I think that the choice should be obvious, as much as it's not what you would prefer.