The pass value is configurable but clients have no way to know if their configuration matches that of a server they have reached
https://github.com/PrivateStorageio/ZKAPAuthorizer/pull/137 introduced the ability to configure the value of a pass on both the client and the server. This is great for deployment flexibility but it does introduce a possible failure point into the system.
What if the client and the server select different values? Currently, no part of the system will validate the two values against each other. If the client thinks a ZKAP is worth less than the server, it will spend more than necessary (wasting some). If the situation is flipped, the client may fail to spend enough and the server will reject the operation.
There isn't really a way to make the situation where the two disagree on the value of a pass work. It isn't ZKAPAuthorizer's job to get the two parties to reach a consensus. However, the failure mode in this situation can at least be explicit and easily understood.
A first step towards this would be for the disagreement to be detectable.