# It's the Harness, Not the Model
*Published: 2026-06-27*
*Tags: ai, claude-code, ai-content*
*Source: https://chrislema.com/its-the-harness*
---## Everyone Keeps Saying "It's Not the Model"

You know how people talk about "harness" when it comes to Claude Code, or Codex or Factory.ai? What they keep saying is that "it's not the model." And they're right.

The model does great work. But it's the harness that makes those models able to produce code that works.

## So What's a Harness?

So what's a harness? It's the code around the model that defines which tools are available, how they work collaboratively, what is off limits, and all that good stuff.

## What If You're Not Writing Code?

What if you're not producing code? Does the idea of a harness disappear?

No way. In fact, over the last week or two, I've built my own. It's called ContentCreator, and it's my one-stop-shop for producing articles.

## The Guides and Guardrails

You've likely heard me talk about a Voice Profile (yourvoiceprofile.com), or a Platform Profile for social media platforms (yourplatformprofile.com). You've likely heard that I created a solution to build Audience Segment profiles (youraudiencesegments.com), and all my frameworks (yourcontentagent.com).

All of those are guides, guardrails, rules to make sure your content has your voice, targets your customers, and leverages your approach to social media platforms.

## But Guardrails Aren't Enough

But that's not enough, right?

A harness is more than guides and guardrails. It's about tools. Declaring which are available and how they work together.

## Bringing Your Own Tools

So I built in a way for you to introduce your own MCPs. I have connections to my website, my newsletter platform (Kit.com), my Google Analytics and Google Search Console, and my tool for pushing content to social.

## Working Across Multiple Models

I also created a way to work with multiple models (Opus 4.8, GPT 5.5, GLM 5.2).

## Stitching the Workflows Together

And then I stitched workflows together. Like, before we brainstorm ideas, we pull data from our existing content, review our target audiences, draw on our search and analytics data, and create topics that would work.

## Why Harnesses Are So Powerful

That little connection is why harnesses are so powerful. Because going to any model and simply asking it to produce an article is a one-shot slop maker.

But when you can pull all of those together, you get some really great (and powerful) brainstormed topics.

[Video: It's the Harness, not the Model](https://www.youtube.com/watch?v=AfCrcfAyRn4)



Want to try it out? ContentCreator is free (and runs on Mac for now) - [https://github.com/chrislema/contentcreator](https://github.com/chrislema/contentcreator)