Justin Melillo · Writing

Muse, MONA, and the AI agent harness

September 24, 2026

Originally published on my Substack.

Meta just announced a slew of new products at Meta Connect. Among them, a new generation of Meta Ray-Bans and new lightweight (100g) VR glasses that I can't wait to try. What I'm most interested in at the moment however, is the Muse AI agent. I love the design. I was an early user of Muse, and I'm excited to see where they take it. I'm interested in Muse because I'm very interested in the future of personalized AI agents.

As the AI model layer gets more commoditized, I think the next exciting frontier is the AI agent harness. Many of my friends ask me what I mean when I talk about harnesses. It's basically the front-end experience or the "wrapper" for the models. While LLMs like ChatGPT and Claude contain all the knowledge in the world, their interfaces are a bit clunky, are designed for more technical users, and fall short when asked to complete fairly specific tasks requiring niche knowledge. Muse appears to be an elegant solution to these problems, and it is really just a harness. It takes the underlying AI model and specializes it for a specific user. In the case of Muse, their user is every non-technical person on planet Earth who wants their own easy-to-use AI assistant.

I'm particularly interested in this because for most of this year, I've been building an AI agent harness for interior designers. It may be the very first AI agent harness designed for interior designers. It is called MONA. It's a way for designers to work with AI without having to do all the skill building and customization themselves. And it's working.

MONA is a specialized AI assistant, trained in interior design and architecture, that interior designers use to help them run their businesses. Rather than give interior designers another rigid software platform, I've built a super-specialized AI assistant, using multiple models, tuned and trained to assist in the workflows of a designer and architect.

The result? A better, more user friendly experience than ChatGPT or Claude. An interface that is fully customizable by an interior designer. MONA is essentially a virtual employee that a designer can talk to through the app, can text on the phone, and can even call and talk to on the phone. MONA maintains a centralized knowledge base for everything happening in a designer's company, keeps a full transcript and recording of all their meetings, has the best AI rendering technology that can generate images, 30s videos, 3D models, keeps track of their finances, saves products they're saving, builds presentations for them, uses the tools they use, and helps generate more leads for them.

I'm really excited for the future of personalized AI, and as a designer myself, I love that I'm building a harness for designers, to help them with mundane aspects of running their business so they have more time to be creative.

The other day, a designer on a larger team at a company told me she was a little nervous, because MONA can do so many jobs that typically a person can do in a studio. This conversation held a lot of gravity and was deeply impactful to me.

There is a lot of talk and speculation around how AI is going to change the way we work. How AI is going to impact jobs, how AI is going to completely change our lives and society. I think for most people, they probably feel helpless, are scared, feel like they have little control over how AI will shape our future. And here I am, having a conversation with a design assistant at a studio, someone who has a family to think about, about how my AI platform is directly affecting how they work.

To be clear, this is a small-scale interior design studio, and the studio owner is not cutting their team. Rather, she is integrating MONA into every aspect of her business because MONA is helping her go from using 10 different software products, spending thousands of dollars every month, to just using one (MONA), only spending hundreds of dollars every month. This studio owner is an early adopter who sees the future of AI, who sees how it can save her entire team time, and who sees how MONA will enable her to scale and grow faster.

The design assistant on her team asked me where that leaves her. It was a deeply vulnerable moment. She asked, "What am I supposed to do with my time now?"

I told her, "Spend it with your family. Spend it with your baby. Find more ways you can help your team and help your studio grow. This is the beauty of AI. Now, you have more time to spend on what matters to you."

This conversation reminded me of the responsibility I have as an entrepreneur. The responsibility we all have to build the future and the world that we actually want to live in, where we improve our lives and those of the people around us.

If you'd like to try MONA and experience firsthand what an AI agent harness can do, or if you know an interior designer who could benefit from using AI in her business, please click and share this link.

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