LTI and Moodle

Hey everyone,

   Very new to moodle and using LTI etc. I've developed an external tool that needs to read the value of a custom checkbox we've added to their profile. Currently we can pull through their name and email - but we're having some serious hangups when trying to pull through these custom parameters. On the LTI config I've set a custom parameter of:

lis_no_id=$User.no_id

Where lis_no_id is the key and $User.no_id would evaluate to the value of the no_id field on that users profile. Currently this key is being sent over but the value isn't being evaluated and is just remaining as a hardcoded string of "$User.no_id" - is my syntax wrong or am I misunderstanding the role of custom parameters? It seems extremely limiting to not be able to send dynamic parameters to me.

I've found https://tracker.moodle.org/browse/MDL-69181 <- this feature request that looks to detail exactly what I'm looking for but I'd be honestly surprised if something like this didn't already exist. All I want to do is create a custom field on a users profile and then send that data to my external tool.

Thanks for reading, any help is much appreciated,

Cameron