[Lunatixz]

You're saying that even though the code run in my directory, as a result of making a JSON-RPC call to Files.GetDirectory then basically ignores what metadata and properties I've attached to my ListItems, and then has to go off searching for the actual values in another, somehow persisted, location? Rather than using the ones that have just been set, by me?

You're confusing infoLabels,Listitems,JSONRPC different things. some infoLabels build from listitems and "Files.GetDirectory" does NOT return a listitem directly.

For your example; "Files.GetDirectory" would run your plugin:// path and build a listitem as per your code.

Yes, that's exactly how I understand it as well. It runs my code, builds a ListItem, and then returns me an incomplete (not including properties) JSON representation of that item. My complaint is that when running code from a particular directory, where these values are set and available (the last time this is the case, before the directory is displayed... because after that, they are unavailable via any method besides a parsed $INFO tag in the skin), there is no reason I can imagine why they can't be returned like any of the other values.

API's work within a schema; predefined keys. I'm not aware of any APIs that allow for custom entries. If a "Custom property" component was ever added to the rpc I imagine It would most likely be a single defined key ex "Properties" that could return a dictionary value set by a developer ie. "Properties":{"Custom_Key_1":"foo","Custom_Key_2":"Bar"}