How to launch "Create case from CustID" from a button?

Success. It even pops it in a slide out which looks nice; end users may disagree…:

Here’s the run through, start with the button triggering app-open:

With no Launch options, I don’t get a new case, just a blank form waiting for me to enter an existing case number:

However adding this to Launch Options:

{   
	"options": {
		"ValueIn": "{Customer.CustID}",
		"Like": "Customer.CustID"
	}
}

makes the magic happen:

Thanks also to @hmwillett for this piece of awesomeness, including the epDebug.context nugget:

After using this I got:
image

I basically threw all that into the Launch Options with very little expectation of success and was amazed when it worked. Peeled back until had just the valueIn and Like fields.

Now back to the “real” work…