Max URI length?

When adding an uri (e.g. "local:track:xxxxx/xxxx.mp3) via Tracklist#add (in javascript) the result is only valid if the number of characters does not exceed 190.
What is that limit? Can it be exceeded somehow?

I started mopidy in verbose mode but no significant error output arises. Just the returned tlTracks array is empty.

Really, nobody else encountered this limitation?

It seems very easy to run into it.

Maybe just http-API related?
Does anybody tried longer URIs?