I actually use the computer as a metaphor. The LLM is the CPU. The harness is the motherboard which controls communication between the CPU and other components like memory, hardrive, and inputs. In other words, how the LLM interacts with the outside world, and outside world with the LLM.

I've been building coding harnesses since 2021 and believed in their value for a long time. Harnesses matter a lot, look at what claude did for Anthropic.

The first analogy that comes to mind, growing out of "harness", is more like harness = harness, model = horse (rather than harness as in climbing harness).

I guess you could say that tokens = hay, and agent = horse and cart, from there? Not sure how useful the hay part is but you could observe from the second that there are many different things you could harness a horse to (also a plough, or a coach, or just a saddle) based on your goal.

I'm a climber so I'm biased but I really liked your climbing harness example because of the configuration you're able to easily make to the harness.

Saying the harness is like a car's chassis doesn't work as well for me because the chassis isn't as configurable as a climbing harness for as little work.

Getting deeper into the climbing analogy you can even swap out the harnesses themselves for wildly different climbs. Like using Claude Code with a bunch of agents for medical software (climbing K2 where that extra padding comes in super handy) and pi.dev with a local model for a respectable web project (sport route where you'll be back in a few hours and it's safe to be a little more exposed).

I'm glad your article made HN, and thank you for pi!