How to conquer Civ with 8 allies?

[miaasma]

The game doesn't show you the odds as it always says 0%. I think its a very viable strategy, it can turn the tables.

it does not always say 0%. putting a level 3 spy in a city state in which the current ally has 40 more influence than you will put the odds at around 80-85%, IIRC, and 85% is the maximum chance at a successful coup. whereas putting a level 1 spy into a city state you are at war with will give you a 0% chance

whether this means it is actually entirely impossible to pull off the coup is something i don't know, and if it is still possible through some extremely small chance that the game just tells you 0, then you could try it given how easy it is to recover level 1 spies for the exceedingly small chance of success. this is why peace blocking with city states is such an effective strategy at high levels