When creating some plugins, the fail to register with Plugin output is empty or not in Json format { XXXXX}

The likely cause is that the JSON output is hits a limit and stops, and the syntax is therefore not interpreted correctly.

I was not able to find the max characters allowable in a JSON output. Can that be clarified?

Also, the error logic, assuming I am correct, might be updated to say.. Max Characters exeeded. Please limit output to XXX or something similar.