> A harness is just supportive scaffolding to run something.

Thank you for the perfect explanation.

Last week in my confusion about the word because Anthropic was using test, eval, and harness in the same sentence so I thought Anthropic made a test harness, I used Google asking "in computer science what is a harness". It responded only discussing test harnesses which solidified my thinking that is what it is.

I wish Google had responded as clearly you did. In my defense, we don't know if we understand something unless we discuss it.