Why we built this

Every app on top of AtClient was doing the same 5 things by hand:

• composing AtKey strings (<id>.<namespace>@<owner>, plus cached: and <recipient>: prefixes);
• fanning out one put per atSign in the share set, with a diff loop on every subsequent change;
• parsing notifications by hand-rolled regex over the key shape;
• inventing a per-app JSON envelope (type tag, version, parents, payload);
• minding the cached: prefix on reads.

5 traps for the unwary, repeated in every app. Getting any one of them slightly wrong cost weeks.

A nicely characterised version of the same idea: every one of these is a place where the principle of least astonishment was getting bent on the way through the SDK boundary.