The Essence of Writing PRDs in Vibe Coding: What I Learned by Doing

I had ideas, motivation, and tools… but still felt stuck when starting projects.

One day, I came across the concept of an *“Interstitial Journal,”* especially useful for ADHD. It involves logging the timing of everything you do throughout the day. This helps track what you’ve done and how much time you’ve spent on each task (since many people with ADHD experience time blindness). It also helps maintain motivation and keep tasks going.

That became the starting point of my idea: building a simple app for myself based on this concept using vibe coding.

The problem was, I didn’t know where to start. I had the concept and features in my head, but when I tried to write a prompt, I didn’t know how to structure it.

So I tried something simple: writing a PRD before coding anything.

What is a PRD?

PRD = Product Requirements Document

A PRD is a document that explains what a product is, why it exists, and how it should work. It helps answer important questions like:

• What are we building?
• Who is it for?
• What problem does it solve?
• What does “done” look like?
• What are the core features?

I learned how to write a full PRD for real-world products in a bootcamp, but here I simplified and adapted it since I was building the product for myself.

My Goal

To create an application based on the interstitial journal concept that:

• Tracks start and end time of tasks (both real-time and manual)
• Minimizes cognitive load
• Reduces overwhelm
• Maintains motivation to keep doing tasks
• Summarizes tracked time

My version of PRD

[embed]

Result

After building based on my PRD, here’s what I created:

1. Daily Dashboard

• Contains a “Start” button to track tasks in real time
• Includes manual logging to track time manually

2. Edit Log

• Allows adding time, categories, and notes for each task

3. Categories

• Lets me assign colors
• Allows adding and editing category names

4. To-Do List

• Allows adding, editing, and deleting daily tasks

5. Summary

• Shows total time tracked
• Breaks down time by category

What I Learned About PRDs in Vibe Coding

From trying vibe coding with a simple PRD, here’s what I learned:

• Writing a PRD helps structure my thoughts clearly and shifts my focus from just design to problem-solving and feature logic
• PRDs help guide how the AI agent builds the app
• PRDs help the AI understand what we are building, who it is for, and how the features and UI should work
• When working with stakeholders, PRDs are essential to keep everyone aligned

What Still Needs Improvement

To get better results, I realized I need to:

• Be more specific in prompts (e.g., specify full-screen layout and tab structure)
• Clearly define UI expectations (e.g., “UI should look like Google Calendar for activity logs”)
• Include full feature behavior (e.g., categories should be editable, not just addable)
• Consider responsiveness (e.g., manual tracking popup exceeded screen edges)

What I’ll Do Next Time

• Write a more detailed and structured PRD
• Be more explicit about UI and interactions
• Include wireframes or low-fidelity designs if possible

Conclusion

Writing a PRD showed me that clarity is what turns ideas into something buildable. Instead of feeling stuck with scattered thoughts, I was able to define the problem, structure the features, and guide the building process more effectively. It also made a big difference in how well the AI understood what I wanted to create. The clearer the PRD, the better the result. Moving forward, improving how I write PRDs will be key to building faster, reducing friction, and turning ideas into real products more smoothly.