My Google fu has failed me.
This has got to be 20-30 years old. Taylor did a story contrasting jazz musicians with classically trained ones. He wrote a jazz piece, then hired the Juilliard String Quartet to rehearse it and make the first public performance of it. IIRC he had a great deal of trouble getting the quartet to move away from the notes on the page and improvise around them. He saw the composition as a kind of rough outline that the musicians would fill out.
In the end, he called the final result a great success. I didn’t think so. To me they sounded like a machine, so tightly scripted and regular. Perhaps they quietly wrote up the exact filler they came up with and played that off the page.
The search is complicated by the fact that Taylor apparently worked several other times with the quartet on pieces he composed to include both string quartets and jazz ensembles.
I would really like to hear this again to see if my more educated ears hear it the same as my younger ears.