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Comment by hombre_fatal | Hacker News Reader

I don't get what's so painful about that description. What would you write instead, specifically? The point is that the harness doesn't completely lock the agent down.

I also don't get what's "really weird" about the article showing up on HN. Should we be completely insulated from how tech topics and which stories show up in non-tech media?

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It’s just the wrong analogy. Harnesses, for the most part, extend an agent’s capabilities and better ground them in the real world through tools and the ability to check external sources, rather than restricting them.

Yet one of the reasons harnesses abstract tool calls is to control what agents can do instead of just yoloing commands and inline python scripts. It's such a central feature, and agents are so hard to control, that harnesses like claude code and codex use an AI classifier to additionally auto-approve tool calls.

It’s both. A harness that enforces valid json to be returned ”restricts” the model.

Okay but is that a relatable sound bite that will make someone click a link? No.

Because that’s not what a harness does. It’s nonsense.

It's one of the things it does, especially in the context of agents doing unexpected things.

Consider what someone who doesn't use AI would take away reading that quote from the article, and what harnesses were actually made for.

> Consider what someone who doesn't use AI would take away reading that quote from the article, and what harnesses were actually made for.

Or you could just communicate the point that you have in your head yourself instead of hoping I do it for you and then arrive at your conclusion when I just reached my own different, independent conclusion after making the same consideration.

Man, how is everyone so wishy washy on this subject? Why not give us the blurb you would write instead for that article and audience?

Harnesses exist to give models tools to do work beyond generating text. People install Claude Code and Codex to have models work inside their repositories and run the code or tests themselves instead of the user having to copypaste code between their IDE and a chat interface. The fact that there's some security built into the harnesses is just a practical consideration, not its primary function.

They control everything the llm can and cannot do. Keeping llms “on the straight and narrow” is arguably their primary function.

Without a harness, all an LLM can do is output text tokens. Nothing else. It's the harness that allows it to read a file, write a file, run commands, start subagents. But even a simple chat application would need a harness, because something has to take the input from the user, mark it up that it's a user message, then parse the LLM's generated tokens and display the message content, or diplay a referenced image inline, or whatnot. All of this is independent of any kind of safety or filtering of naughtiness.

The harness gives the model the barbed wire fence but also the bolt cutters. I think it's a pretty apt analogy.

The main role of the harness is not any kind of moderation or alignment, but simply making a text generation engine do anything other than output a long stream of text.

It's like saying that the role of a car's wheel is to hold wheel clamps. Yes, you can put wheel clamps (or snow chains etc) on a wheel, but the wheel's overwhelming role is to rotate and propel the car forward, and there is no driving without having wheels, you just have an engine with parts rotating inside. Bad analogy I know but, a harness is not a safety feature. Imagine that you're trying to explain cars to someone who has never seen one and you never say that the wheel's purpose is to rotate and move the car from A to B, you just say that it's something to put chains on when it snows.

I guess the name sounds like some kind of straightjacket etc. But think of it more as the harness you put on a workhorse or ox. It's the thing that connects it to the workload in the first place. They are not the blinders of the horse.

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