| name | product-design |
| description | Design MVPs for web, mobile, and SaaS applications through adaptive interviews that achieve buildable clarity. Use when a user wants to define, scope, or document an application idea, or when they mention MVP, product requirements, PRD, app idea, or need help turning a concept into something implementable. |
Product Design
Interview users to extract implementation-ready requirements, then produce a PRD with enough detail to build with minimal ambiguity.
Interview Workflow
Phase 1: Core Concept (always)
Start here. Get the essential shape of the product.
- What is it? One sentence describing what the app does
- Who uses it? Primary user roles (2-4 max for MVP)
- Core actions? What can each role do? (aim for 3-5 key actions per role)
- Platform? Web, mobile, both? Any platform constraints?
Exit when: You can explain the app to someone in 30 seconds.
Phase 2: User Scenarios (always)
For each role, define concrete scenarios at the feature level.
For each key action, ask:
- "Walk me through exactly what happens when [role] does [action]"
- "What information do they need to see? What do they input?"
- "What happens after? Where do they end up?"
Probe for edge cases:
- "What if [input is missing/invalid]?"
- "What if [user cancels midway]?"
- "Are there limits? (max items, required fields, etc.)"
Exit when: You could sketch every screen and know what each button does.
Phase 3: Technical Context (always)
Nail down the tech stack. The PRD should specify exactly what to build with.
| Topic | Key questions |
|---|---|
| Frontend | Web app, mobile (React Native, Flutter, native), or both? Which framework (React, Vue, Next.js, etc.)? |
| Backend | BaaS (Supabase, Firebase, Convex)? Custom API (Node, Python, Go)? Serverless functions? |
| Database | Postgres, MongoDB, SQLite? Managed by BaaS or self-hosted? |
| Deployment | Vercel, Netlify, Railway, Fly.io? App stores for mobile? |
| Auth | Built-in (Supabase Auth, Firebase Auth)? Third-party (Auth0, Clerk)? Social providers needed? |
| Integrations | Which external services? What data flows between? |
| Payments | Stripe, RevenueCat? Subscription vs one-time? |
| Notifications | Email (Resend, SendGrid)? Push? What triggers them? |
| Files/Media | Upload types? Size limits? Storage (S3, Supabase Storage, Cloudinary)? |
Exit when: You could set up the project and install dependencies with no ambiguity.
Phase 4: Scope Boundaries (always)
Explicitly define the MVP boundary.
Ask:
- "What's the one thing this MVP absolutely must do well?"
- "What features are you tempted to include but could wait for v2?"
- "Any hard constraints? (timeline, budget, must use X technology)"
Create explicit IN/OUT lists. Push back on scope creep:
- "That sounds like a v2 feature. For MVP, could we [simpler alternative]?"
Exit when: Clear line between MVP and future work.
Interview Principles
Go deeper when:
- Answer is vague ("users can manage their stuff")
- Multiple interpretations possible
- Edge cases not addressed
- Implementation would require guessing
Move on when:
- Answer is concrete and specific
- You could write the code/design the screen
- Edge cases covered or explicitly deferred
Phrase questions as:
- "Walk me through..." (gets concrete steps)
- "What exactly happens when..." (forces specificity)
- "Show me an example of..." (grounds in reality)
- "What if..." (surfaces edge cases)
PRD Template
After the interview, produce this document:
# [Product Name] - MVP PRD
## Overview
[2-3 sentences: what it is, who it's for, core value proposition]
## Roles
| Role | Description | Key Permissions |
|------|-------------|-----------------|
| [Role 1] | [Who they are] | [What they can do] |
## User Scenarios
### [Scenario Name]
**Role:** [Which role]
**Goal:** [What they're trying to accomplish]
**Flow:**
1. [Step with specific UI/action]
2. [Next step]
3. [Outcome]
**Edge Cases:**
- [Edge case]: [How it's handled]
**Acceptance Criteria:**
- [ ] [Specific, testable criterion]
- [ ] [Another criterion]
[Repeat for each scenario]
## Scope
### In Scope (MVP)
- [Feature/capability 1]
- [Feature/capability 2]
### Out of Scope (Future)
- [Deferred feature 1] - [brief reason why deferred]
- [Deferred feature 2]
## Technical Context
### Tech Stack
| Layer | Choice | Notes |
|-------|--------|-------|
| **Frontend** | [Framework - e.g., Next.js, React Native] | [Any specific libraries] |
| **Backend** | [e.g., Supabase, custom Node API] | [Architecture notes] |
| **Database** | [e.g., Postgres via Supabase] | [Key considerations] |
| **Auth** | [e.g., Supabase Auth with Google] | [Providers needed] |
| **Deployment** | [e.g., Vercel, App Store] | [Environments] |
### Integrations
| Service | Purpose | Data Flow |
|---------|---------|-----------|
| [Service] | [Why needed] | [What data, which direction] |
### Key Entities
[Only if helpful - brief description of core data objects and relationships]
### Constraints
- [Any technical constraints, required technologies, etc.]
## Open Questions
- [Any unresolved items that need answers before/during implementation]
Workflow Summary
START
│
▼
┌─────────────────────────┐
│ Phase 1: Core Concept │ ◄── Always. Get the 30-second pitch.
└──────────┬──────────────┘
│
▼
┌─────────────────────────┐
│ Phase 2: User Scenarios │ ◄── Always. Could you sketch every screen?
└──────────┬──────────────┘
│
▼
┌─────────────────────────┐
│ Phase 3: Technical Ctx │ ◄── Always. Nail down the tech stack.
└──────────┬──────────────┘
│
▼
┌─────────────────────────┐
│ Phase 4: Scope Boundary │ ◄── Always. Clear MVP vs future line.
└──────────┬──────────────┘
│
▼
┌─────────────────────────┐
│ Generate PRD │
└─────────────────────────┘
Exit Criteria
Ready to produce PRD when ALL are true:
- Can explain the app in 30 seconds
- Could sketch every screen for MVP
- Know what every button/action does
- Edge cases addressed or explicitly deferred
- Clear MVP boundary established
- Tech stack fully specified (frontend, backend, database, auth, deployment)
- No technical unknowns that block implementation