...
Conversely when you get shortName, ecCodes looks for the best match of the keys listed in the full definition of shortName (not only cape) and will return "cape" only if the following are true:
discipline == 0 parameterCategory == 7 parameterNumber == 6 typeOfFirstFixedSurface == 1 typeOfSecondFixedSurface == 8
in the message and there isn't a better match of keys in the list.
...