This specification does not have clear specifications of the callback data

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An example is the merkleProof callback data, there must be some required merkle proof format in the callbackPayload. At the moment the reference implementation gives me targetType == "header". But what if gives me one of the other formats? What if it can never give me one of the others and I have to handle it because the specification does not make it clear I do not have to ever handle receiving it?

[rt121212121]

I think someone should go through and lock down all the different fields in all the different data structures in this specification, including stating date standards.

[rt121212121]

Additionally, I am told that MAPI will send the merkle proof if your transaction is reorged. It would be good if this can be detailed and clearly laid out how it should happen from a miner perspective and what a developer should expect to see. This has the repercussions of requiring the developer to keep the callback URL open (specifically a peer channel they may be paying to have hosted) for some period of time. I expect that it should be possible to explicitly state, the callback URL should be open until the transaction has six confirmations at which point it will never receive reorged merkle proof notifications.

[rt121212121]

Every single point that is not elaborated on to give full details means that developers have opportunity to misinterpret how to implement this. And that miners have opportunity to misinterpret how to operate this as a service.