Clojurians Log v2

What exactly are the arguments that domino handler functions take? What is the ctx? the whole value of the domino map? The next two args are input and output maps presumably, but what are those maps? How is a transaction transformed into an input map?

The readme says > The handler accepts three arguments: a context containing the current state of the engine, a list of the input values, and a list of the output values. The function should produce a vector of outputs matching the declared :outputs key. For example: But then the destructuring in the example suggests the second and third arguments and the return values are maps not lists?