
A PRD (Product Requirements Document) is your blueprint. It's your clear thinking written down. A good PRD prevents building the wrong thing, scope creep, expensive rebuilds, and "that's not what I meant" moments.
Clear requirements stop you from building features nobody needs
Defined boundaries keep projects on track and on budget
Get it right the first time instead of costly do-overs
Everyone knows exactly what you're building and why
What problem are you solving?
Example: "Employees waste an average of 2 hours per day searching through company documents to find information. This reduces productivity and leads to inconsistent answers."
What are you trying to achieve?
Example:
Primary: Reduce time to find information by 70%
Secondary: Provide consistent, accurate answers
Success: < 30 seconds to get answer, > 80% accuracy
Who uses this and why?
Example:
As an employee, I want to ask "What's our vacation policy?" and get an accurate answer in under 30 seconds
As an admin, I want to upload new documents and have them automatically available in the system
What must it do?
How well must it work?
What technology is needed?
Example:
What data is needed?
Example:

What does the UI need?
Example:
Chat interface for questions
Document upload interface
Answer display with sources
Mobile-responsive design
How do you measure success?
Target for query responses
Target accuracy rate
Target star rating
Target reduction in search time
What are the limitations?
What could go wrong?
Which platform/framework?
Example:
Platform: Next.js
Reason: Need API routes for document processing and chat
Alternative considered: Vite (rejected - no API routes)
Employees waste 2 hours/day searching documents
Reduce search time by 70%, provide accurate answers, support 1,000 users
Employee: Ask questions, get answers. Admin: Upload documents, manage system
Natural language questions, document search, answer with citations, document upload
< 3s response time, 99.5% uptime, support 1,000 users
Vector DB (Pinecone), OpenAI APIs, document processor
10,000+ documents, PDF, Word, text formats
Chat interface, upload interface, mobile-responsive
< 3s response, 80% accuracy, 4/5 satisfaction
$500/month budget, 3 month timeline
Cost overrun → Caching, Low accuracy → Fine-tune, Slow response → Optimize
Next.js (need API routes)
"Make it good" isn't specific
Can't measure success
Unrealistic expectations
Surprised by problems
Missing critical information
For AI Systems, Also Include:
Which models and why
When to use AI vs. fallback
What if AI fails?
AI API costs
How is data handled?
How to prevent bias?
Don't skip
Vague = problems later
Review with stakeholders
PRD is living document
Use during development
After completing PRD:

Product Requirements Document for AI Systems