Behind the Craft · Sunday, June 28, 2026
Jess Yan argues that maximum performance for AI models is achieved when the model and its harness are developed together. She notes that models are always tested in conjunction with specific harnesses, creating a symbiotic relationship.
“Do you think the model should be developed with the harness, like, like have they kind of joined at the hip?”
“I think I am quite biased, but I also think that it is impossible to get the maximum possible performance without tying together the harness and the model.”
“However, you know, when we test our models and when we are assessing their performance, we always have to test it in conjunction with a harness, and are we going to test it with all the different harnesses in the world? We're going to select the harnesses that we have built.”