Write a PRD with an AI agent (without the fluff)

An AI agent will write you a product requirements document in about ninety seconds. It'll also pad it into five pages of plausible-sounding filler in the same ninety seconds. Both happen by default, which is why "have the agent write the PRD" produces either something genuinely useful or something that wastes everyone's time — depending entirely on how you direct it.

Here's how to draft a PRD with an agent that stays tight and build-ready, instead of the bloated kind nobody reads.

Why draft a PRD with an agent

A PRD is the source of truth for what to build and why. Drafting one with an agent is worth doing because the agent is fast at structure — it'll organise your thinking into clean sections, surface questions you hadn't considered, and turn a messy brain-dump into something readable in moments.

What it can't do is supply the content — the actual decisions, constraints, and intent. That's yours. The agent is a fast drafter and a useful interrogator, not a source of requirements.

Give it context, not a blank prompt

The single biggest determinant of PRD quality is how much context you bring. Hand an agent "write a PRD for a referral feature" and you get generic, padded requirements that could apply to any product. Hand it the problem, the users, the constraints, the decisions already made — and it produces something specific and useful. The teams writing the best AI-assisted PRDs all say the same thing: provide detailed context up front rather than expecting a complete document from a thin prompt.

Stuart Leo

A blank prompt gets you a generic PRD. The agent's quality is capped by the context you bring to it.

So start by dumping what you know — even messily. The problem, who it's for, what you've decided, what you're unsure about. The agent shapes that into a PRD far better than it invents one from nothing.

The sections that matter

Direct the agent toward the sections that actually drive a build, and skip the ceremonial ones:

• The problem and who it's for — one tight paragraph.
• What it must do — the core requirements.
• Non-goals — what it must not do. The agent will under-weight this, so push for it. It's the section that stops over-building.
• Decisions and constraints — the choices already made.
• Acceptance criteria — ideally things you can run.

If a section isn't one of these, question whether it earns its place. Most PRD bloat is sections that exist out of habit, not need.

Cutting the fluff the agent loves

Models pad. Left alone, an agent adds hedging, restates the obvious, and inflates a one-line decision into a paragraph — length that reads thorough and buries the actual decisions. So the last step is always to cut.

Read the draft and delete everything that isn't a decision or a requirement. If a sentence doesn't change what gets built, it goes. A tight one-page PRD an agent can act on cleanly beats a five-page one where the three real constraints are lost in filler. Ask the agent directly to "cut this to the decisions" — it's good at that when told.

From PRD into the build

A PRD isn't the end — it's the top of a chain. Once it's tight, it cascades down into the scoped briefs an agent actually builds from, which is the Cascade: PRD decides, brief executes. Commit the PRD into your contextbase so every brief derived from it — and every agent working on the feature — builds against the same source of truth.

An agent drafts a PRD in minutes — your job is to bring the context and cut everything that isn't a decision.

Start here: see what a PRD is and why agents need one, the Cascade from PRD to brief, or read the method.