API Docs response Message vs real response message

Why does the API Docs response mention that the response message for one of the POST methods is

“code”: 0,
“message”: “string”

whereas the actual result of executing the API results in the following json


I assume(d) that I can straightaway write some JS to look for “code”. Instead I have to execute the API and see if the return key is “code”, “status_code” or something else?

The data is being posted to the included MongoDB installation. So I expect the response messages to adhere to what is shown in API Docs. That leaves me a little confused. Am I doing something incorrect or will the key keep changing - would it return just “status” on a different / new version?