*question*What is the difference between trait and intent? more detail

[xyFreddie]

Hi. I do not understand the difference between trait and intent. Trait can also be customised and add several values. And it's also based on the whole sentence.
Do intent/trait trained based on entity? (do the recognized entity serve as input feature of the intent/trait training?
In intent, there is also an out of scope option. What is the difference between this option and another intent called "out of scope"?
Do you have academic paper or only docs for the platform?

Another more detailed question. I want to identify what subfield(s) can be used to answer the input questions. A question can be categorized to one major subfield A, but also possible others(with a confidence threshold) B, C. Should I use intent or trait in this case?
I also want to identify if the question is unclear, for example: "Why are the invoices paid late" I want it to recognize in here the "late" is ambiguous and this is a unclear question regarding [time], and I would probably return something like "please specify the [time]"
Thank you.