What happens in Xano doesn't in Swagger

I'm not doing something right... Michael U. helped resolve getting and using a variable created in the function stack (it was an object not a scalar value). In any case my Xano API functions properly as a POST in the Xano UI. Jumping over to Swagger and using the same input I get a 500 status error. Since this is a POST I have to use Swagger to test its functionality; I can't just pop the URL into a browser.
Nothing fancy here, just JSON that generates no errors
[favorites 404 error 04.jpg]But somehow this input generates the error below.
This appears to be my ignorance and not the server; it knows what to expect better than I do. This same API endpoint works fine in Xano.[favorites 404 error 05.jpg]mydata.art_favorite is 'true' (no quotes) is generating the error. Stepping back a bit on the responses there is the [object, Object] array that looks suspicious but I don't know how to address that or where.[favorites 404 error 06.jpg]