Breeder's promise only works for live breedings. it doesn't do anything for freezer items like straws or embryos 

That would been great to know. Why doesn't the coin say that? I hate that information like that is just not available until you didn't know you needed to know that information…very frustrating. Still having 5 straw fail is frustrating and odds using straws make not worth the money unfortunately.

I had go double check but yea the coin doesn't tell you that at all. What other coins do not work form hind information of not doing this or that 😂 I been wasting all them now. Like go figure.

Breeders Promise

A single-use item that changes the breeding fail possibility to 0. Guarantees a foal next breeding

To be fair, it doesn't necessarily mention anything in regards to using straws/eggs, as I've always interpreted it as live breedings but perhaps a feature request could be drawn up and have specific items, made more clearer, like this for example.

The wiki is pretty clear that there's still a fail rate when using the straws and the wiki also says Breeder's Promise doesn't work on straws https://horsefable.wiki/straws-eggs/

I agree that it could be more clear on the item itself but the information is very much available to any user

I think it specifying “guarantees a foal next breeding” is enough! using straws or embreyos is always referred to as “implantation” both irl and by the site, not as breeding. There's plenty more info that could be added to descriptions of various items, however it's already starting to look a bit cluttered with just a few lines, let alone paragraphs. As long as the more detailed info is found easily in the wiki, it's fine to keep descriptions short.

Maybe it could have what you noted earlier, Mouse, and just be “guarantees a foal on the next live breeding”? To me that isn't too cluttery and can, hopefully, help differentiate between the two.

As for the Wiki part, I'm so used to it being a pain to navigate/doesn't have complete information, that I tend to avoid/ignore it unless I need it for Discipline use and that is easily on speed dial for me to pull up and bypass trying to navigate the Wiki on mobile. I think on desktop, it has gibberish icons that makes a search a pain. On occasion I have used it for simplier things but it's rather an out of sight, out of mind kind of thing.