Your PRD Isn't Bad Because It's Too Short. It's Bad Because Nobody Knows What Success Looks Like

At Sonic Linker, we had to ship our core AI product in 3 months. I was on the founding team, and we didn't have time for perfect documentation. My first PRD was 2.5 pages, mostly bullet points and rough wireframes.

It worked because everyone on the team could tell you exactly what success looked like. Not the business goals or the vision statement. I mean the actual, testable thing we were building.

That's when I realized most PRDs fail not because they're missing sections, but because they're missing clarity on what done actually means.

The Problem With Template-Driven PRDs

When I moved to Finvestfx, I inherited a 12-page PRD for a treasury management feature. Beautiful document. Had all the right sections: user stories, acceptance criteria, edge cases, the works.

Three weeks into development, the engineering lead asked me: "So when the user uploads a bank statement, should we auto-categorize transactions or let them do it manually?"

It wasn't in the PRD. Neither were about 15 other critical decisions.

The doc had everything a good PRD is supposed to have. But it didn't answer the questions people actually needed answered to build the thing.

That's the trap. We focus on format over function. A good PRD isn't good because it follows a template. It's good because it makes decisions clear and prevents the team from getting stuck.

What Actually Makes a PRD Good

Here's what I've learned works, across shipping products at 4 different companies:

Start with the decision you're making, not the solution you're building. At NJ Group, I worked with insurance advisors and IFAs on product adoption. One PRD I wrote was literally titled "Decision: Do we build a mobile app or optimize the mobile web experience first?" That framed everything else. The PRD became a tool for alignment, not just documentation.

Define done in a way engineers can test. Not "user can manage their portfolio." Instead: "user can add a stock, set a target price, and receive a notification when it's hit, all within 30 seconds." I learned this the hard way at Stampede Capital when vague acceptance criteria led to three rounds of rework on a pre-IPO equity feature.

Call out what you're explicitly NOT doing. This is the most underrated part of a good PRD. At Sonic Linker, I had a section called "Out of Scope for V1" in every doc. It saved us from scope creep at least a dozen times. When someone suggested adding a feature mid-sprint, I could point to that section and say "we already decided to punt that."

Put the riskiest assumption at the top. If your PRD buries the big unknown on page 7, you're doing it wrong. I started putting a "Biggest Risk" callout right after the summary. For one Finvestfx feature, it was "we're assuming enterprises will actually use this instead of their existing Excel workflows." That changed how we approached the entire build and led us to add an Excel import feature we hadn't originally planned.

The Real Test

Here's how I know if a PRD is actually good: I hand it to an engineer who wasn't in the planning meetings. I ask them to read it and tell me what they'd build.

If they can describe the feature back to me and their version matches what's in my head, the PRD is good. If they're guessing or asking clarifying questions about core functionality, I need to rewrite it.

I did this at Sonic Linker with a junior dev on the team. He read my PRD for a new AI linking feature and immediately built a rough prototype that was 80% right. That told me the doc was clear.

At Finvestfx, I did the same test with a different PRD and got back three different interpretations from three different engineers. That told me I'd failed, even though the doc looked comprehensive.

The Takeaway

Stop optimizing for complete documentation. Start optimizing for complete clarity.

A good PRD isn't measured by page count or sections filled out. It's measured by whether your team can build the right thing without constantly coming back to you for answers.

That means being specific about success criteria, honest about what you don't know, and clear about what you're choosing not to do.

Your PRD should make decisions, not just describe features. If it does that, it's good. Even if it's only two pages.