Do Software Products Still Need a User Interface?

Karri Saarinen says software products still need a user interface when people have to share one account of the truth, and sometimes they do not. Agents are often the better way in and the better way out. A person can talk through a complex workflow that would take a long path of buttons, and the agent does the work. A large pile of information is a poor thing to browse. He uses 40,000 customer requests as the example: nobody can read that list, so the agent can synthesize it, structure it, or find what matters, and the team does not have to build every reporting screen.

The interface still matters because an agent is not a source of truth. It can answer two people differently, leave an item out, change the order, or hallucinate. A roadmap on a screen is the same roadmap for everyone. What one person sees is what the next person sees, and the company can agree on it. Hierarchy and grouping show what is important and how the pieces relate.

An agent could build that screen if someone gave it the right guidance. The remaining question is where the shared truth lives. Even a command line, an API, or MCP still needs a designed system: what a project is, which properties it has, and which workflows it runs. That description still shapes how people think about the product.