Documentation for payload of endpoints

[DominikMoelter]

Is there any documentation, which key exist for the different endpoints?
I just found the reference for the WebOS Luna Service API, but just some payload key worked for me. Most of them not.

[chros73]

Which endpoint for example? Take a look at bscpylgtv for more docs (those came from the decompiled firmwares).
https://github.com/chros73/bscpylgtv
I only know this API reference:
https://www.webosose.org/docs/reference/ls2-api/com-webos-service-power2/

[DominikMoelter]

I think I'm missing something.
I'm using Home Assistant with the "LG webOS Smart TV" integration which is using this project. In the documentation of this Home Assistant integration you can find a chapter for sending commands to the tv. In this example the endpoint "system.launcher/open" is used which can also be found in the endpoint file of this repo.
My question is how do I know which payload keys are valid for each endpoint and if they are mandatory or optional?