I have been playing around with Codex for the last week or so and I have shaken to my core. I am amazed. I mainly write Java so I decided to try and make an IntelliJ plugin for it. It can complete normally using keybinds OR you can select a function and it can come up with and insert javadocs for the function. Here is an example of a complicated javadoc it generated:
Thanks! The plugin isn’t on the marketplace yet, right now I just have my API key hardcoded in and I need to add a setting for your API key. I also have to fix some formatting issues first but as soon as I do put it on it I’ll let you know. Also, yes Codex helped me right its own plugin 
There is also this list:
** Maybe they don’t work with CODEX. So they need to be verified.
Thanks for the clarification.
Any chance this thing will be available in PHPStorm? I’m a taker.