It is enum with string key "mode" You can use my tool for reading descriptors...  https://github.com/jardicc/ActionManagerHumanizer

#include Humanizer.jsx
...
var descriptorContent = Humanizer.descriptorToObject(executeActionGet(ref));

Blend mode enums. Some tools/actions might use only specific enums.

It is enum with string key "mode" You can use my tool for reading descriptors...

Otherwise you need to..

1. get number of keys in action descriptor .count
2. loop all keys and their names .getKey(index)
3. it returns typeID so you have to use charIDToTypeID() or stringIDToTypeID() and now you should know name of properties inside descriptor
4. then you can use .getType(typeID) and it returns what data type the property is
5. And finally you can decide if you will use getString() or getEnumerationValue() or another data type method

https://github.com/jardicc/ActionManagerHumanizer

#include Humanizer.jsx
...
var descriptorContent = Humanizer.descriptorToObject(executeActionGet(ref));

Blend mode enums. Some tools/actions might use only specific enums.