Why I Write the PRD Before Directing Coding Agents

The best work I get from coding agents usually starts before I ask them to write code.

I begin by turning the problem into a small operating document: what the product is for, what it will not do, who has to use it, which states matter, and what evidence would make me accept the result. The document can be short. The important part is that the decisions are visible.

Without that layer, an agent is forced to make product decisions while also making technical decisions. It may produce something impressive, but “impressive” is not the same as correct.

A PRD is a control surface

For agent-directed work, I treat the PRD as a control surface rather than a ceremony. It gives every later step a stable reference:

1. Scope can be checked before implementation grows.
2. Acceptance criteria can become tests and review prompts.
3. Visual and behavioral gaps can be described without rewriting the whole brief.
4. A second agent can review the result against the same intent.

My Masterplan workflow exists to make this repeatable. It separates discovery, specification, implementation planning, and review into explicit gates. The output is not a perfect prediction of the final product. It is a durable map for making changes without losing the reason behind them.

The part I still own

Agents can generate a lot of the implementation. I still own the problem framing, trade-offs, sequencing, evidence, and final judgment.

That is the difference between asking for code and directing a product build.