name: rapid-prototyper
description: Creates minimal working prototypes for quick idea validation. Single-file when possible, includes test data, ready to demo immediately. Use when user says "prototype", "MVP", "proof of concept", "quick demo".
priority: MEDIUM
conflicts_with: [browser-app-creator]
use_when:
- User wants to VALIDATE AN IDEA quickly
- User needs a PROOF OF CONCEPT
- User wants MINIMAL implementation
- User doesn't care about polish or production-readiness
- User says "prototype", "MVP", "quick", "test"
avoid_when:
- User wants a COMPLETE application
- User wants ADHD optimization
- User wants production-ready code

Rapid Prototyper

Purpose

Fast validation through working prototypes. Creates complete, runnable code to test ideas before committing to full implementation:
1. Recalls your preferred tech stack from memory
2. Generates minimal but complete code
3. Makes it runnable immediately
4. Gets you visual feedback fast
5. Saves validated patterns for production

For ADHD users: Immediate gratification - working prototype in minutes, not hours.
For aphantasia: Concrete, visual results instead of abstract descriptions.
For all users: Validate before investing - fail fast, learn fast.

Activation Triggers

• User says: "prototype this", "quick demo", "proof of concept", "MVP"
• User asks: "can we build", "is it possible to", "how would we"
• User mentions: "try out", "experiment with", "test the idea"
• Before major feature: proactive offer to prototype first

Core Workflow

1. Understand Requirements

Extract key information:

{
  feature: "User authentication",
  purpose: "Validate JWT flow works",
  constraints: ["Must work offline", "No external dependencies"],
  success_criteria: ["Login form", "Token storage", "Protected route"]
}

2. Recall Tech Stack

Query context-manager:

search memories:
- Type: DECISION, PREFERENCE
- Tags: tech-stack, framework, library
- Project: current project

Example recall:

Found preferences:
- Frontend: React + Vite
- Styling: Tailwind CSS
- State: Zustand
- Backend: Node.js + Express
- Database: PostgreSQL (but skip for prototype)

3. Design Minimal Implementation

Prototype scope:
- ✅ Core feature working
- ✅ Visual interface (if UI feature)
- ✅ Basic validation
- ✅ Happy path functional
- ❌ Error handling (minimal)
- ❌ Edge cases (skip for speed)
- ❌ Styling polish (functional only)
- ❌ Optimization (prototype first)

Example: Auth prototype scope

✅ Include:
- Login form
- Token storage in localStorage
- Protected route example
- Basic validation

❌ Skip:
- Password hashing (use fake tokens)
- Refresh tokens
- Remember me
- Password reset
- Email verification

4. Generate Prototype

Structure:

prototype-{feature}-{timestamp}/
├── README.md              # How to run
├── package.json           # Dependencies
├── index.html             # Entry point
├── src/
│   ├── App.jsx           # Main component
│   ├── components/       # Feature components
│   └── utils/            # Helper functions
└── server.js             # If backend needed

Example: Auth Prototype

package.json:

{
  "name": "auth-prototype",
  "type": "module",
  "scripts": {
    "dev": "vite",
    "build": "vite build"
  },
  "dependencies": {
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-router-dom": "^6.20.0",
    "zustand": "^4.4.7"
  },
  "devDependencies": {
    "@vitejs/plugin-react": "^4.2.1",
    "vite": "^5.0.8"
  }
}

src/App.jsx:

import { useState } from 'react';
import { BrowserRouter, Routes, Route, Navigate } from 'react-router-dom';
import { useAuthStore } from './store';

function LoginForm() {
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');
  const login = useAuthStore(state => state.login);

  const handleSubmit = (e) => {
    e.preventDefault();
    // Prototype: Accept any credentials
    if (email && password) {
      login({ email, token: 'fake-jwt-token' });
    }
  };

  return (
    <div style={{ maxWidth: 400, margin: '100px auto' }}>
      <h1>Login</h1>
      <form onSubmit={handleSubmit}>
        <input
          type="email"
          value={email}
          onChange={(e) => setEmail(e.target.value)}
          placeholder="Email"
          style={{ display: 'block', width: '100%', margin: '10px 0', padding: 8 }}
        />
        <input
          type="password"
          value={password}
          onChange={(e) => setPassword(e.target.value)}
          placeholder="Password"
          style={{ display: 'block', width: '100%', margin: '10px 0', padding: 8 }}
        />
        <button type="submit" style={{ padding: '10px 20px' }}>
          Login
        </button>
      </form>
    </div>
  );
}

function Dashboard() {
  const { user, logout } = useAuthStore();

  return (
    <div style={{ maxWidth: 800, margin: '50px auto' }}>
      <h1>Dashboard</h1>
      <p>Welcome, {user.email}!</p>
      <p>Token: {user.token}</p>
      <button onClick={logout} style={{ padding: '10px 20px' }}>
        Logout
      </button>
    </div>
  );
}

function ProtectedRoute({ children }) {
  const isAuthenticated = useAuthStore(state => state.isAuthenticated);
  return isAuthenticated ? children : <Navigate to="/login" />;
}

export default function App() {
  return (
    <BrowserRouter>
      <Routes>
        <Route path="/login" element={<LoginForm />} />
        <Route
          path="/dashboard"
          element={
            <ProtectedRoute>
              <Dashboard />
            </ProtectedRoute>
          }
        />
        <Route path="/" element={<Navigate to="/dashboard" />} />
      </Routes>
    </BrowserRouter>
  );
}

src/store.js:

import { create } from 'zustand';
import { persist } from 'zustand/middleware';

export const useAuthStore = create(
  persist(
    (set) => ({
      user: null,
      isAuthenticated: false,
      login: (user) => set({ user, isAuthenticated: true }),
      logout: () => set({ user: null, isAuthenticated: false }),
    }),
    {
      name: 'auth-storage',
    }
  )
);

README.md:

# Auth Prototype

Quick prototype to validate JWT authentication flow.

## Run

```bash
npm install
npm run dev

Open http://localhost:5173

Test

1. Go to /login
2. Enter any email and password
3. Click Login
4. Should redirect to /dashboard
5. Refresh page - should stay logged in
6. Click Logout - should return to /login

Notes

• Uses fake tokens (no real JWT validation)
• No password hashing
• Minimal styling
• No error handling

Next Steps if Validated

1. Implement real JWT signing/verification
2. Add password hashing with bcrypt
3. Add proper error handling
4. Add refresh token flow
5. Add validation and security measures

### 5. Save to Artifacts

```bash
# Save complete prototype
# Linux/macOS: ~/.claude-artifacts/prototypes/auth-{timestamp}/
# Windows: %USERPROFILE%\.claude-artifacts\prototypes\auth-{timestamp}\
~/.claude-artifacts/prototypes/auth-{timestamp}/

6. Present to User

✅ Auth prototype ready!

📁 Location (Linux/macOS): ~/.claude-artifacts/prototypes/auth-20251017/
📁 Location (Windows): %USERPROFILE%\.claude-artifacts\prototypes\auth-20251017\

🚀 To run:
cd ~/.claude-artifacts/prototypes/auth-20251017
# Windows: cd %USERPROFILE%\.claude-artifacts\prototypes\auth-20251017
npm install
npm run dev

🎯 Test flow:
1. Visit http://localhost:5173/login
2. Enter any email/password
3. Click Login → Redirects to Dashboard
4. Refresh → Stays logged in
5. Click Logout → Returns to Login

✅ Validates:
- JWT token flow works
- Protected routes work
- State persistence works
- React Router integration works

❌ Not included (yet):
- Real JWT validation
- Password hashing
- Error handling
- Production security

**Does this validate what you needed?**
- If yes: I'll build production version
- If no: What needs adjusting?

Prototype Templates

Single-File HTML App

For quick UI demos:

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Prototype</title>
  <script src="https://unpkg.com/vue@3"></script>
  <style>
    body { font-family: sans-serif; max-width: 800px; margin: 50px auto; }
  </style>
</head>
<body>
  <div id="app">
    <h1>{{ title }}</h1>
    <button @click="count++">Count: {{ count }}</button>
  </div>

  <script>
    const { createApp } = Vue;
    createApp({
      data() {
        return {
          title: 'Quick Prototype',
          count: 0
        }
      }
    }).mount('#app');
  </script>
</body>
</html>

When to use: UI-only features, visual concepts, no build step needed

React + Vite

For complex UI with state management:

npm create vite@latest prototype-name -- --template react
cd prototype-name
npm install
# Add feature code
npm run dev

When to use: Multi-component features, routing, state management

Node.js Script

For backend/API prototypes:

// prototype.js
import express from 'express';

const app = express();
app.use(express.json());

app.post('/api/users', (req, res) => {
  // Prototype logic
  res.json({ success: true, user: req.body });
});

app.listen(3000, () => {
  console.log('Prototype running on http://localhost:3000');
});

When to use: API endpoints, data processing, backend logic

Python Script

For data analysis/processing:

# prototype.py
def process_data(data):
    # Prototype logic
    return [item * 2 for item in data]

if __name__ == '__main__':
    sample = [1, 2, 3, 4, 5]
    result = process_data(sample)
    print(f"Input: {sample}")
    print(f"Output: {result}")

When to use: Data processing, algorithms, automation

Context Integration

Recall Preferences

Before creating prototype:

// Query context-manager
const techStack = searchMemories({
  type: 'DECISION',
  tags: ['tech-stack', 'framework'],
  project: currentProject
});

const preferences = searchMemories({
  type: 'PREFERENCE',
  tags: ['coding-style', 'libraries'],
  project: currentProject
});

// Apply to prototype
const config = {
  framework: techStack.frontend || 'React',
  styling: techStack.styling || 'inline-styles',
  state: techStack.state || 'useState',
  build: techStack.build || 'Vite'
};

Save Validated Patterns

After user validates prototype:

User: "This works perfectly! Build the production version"

# Save pattern as PROCEDURE
remember: Authentication flow pattern
Type: PROCEDURE
Tags: auth, jwt, react-router, zustand
Content: Validated pattern for JWT auth:
- Zustand store with persist middleware
- React Router protected routes
- Token in localStorage
- Login/logout flow
Works well, use for production

Learn from Iterations

Track what gets changed:

// If user asks for modifications
"Can you add password validation?"
"Make the form prettier"
"Add loading state"

// Track patterns
if (commonRequest) {
  saveMemory({
    type: 'PREFERENCE',
    content: 'User commonly requests password validation in prototypes',
    tags: ['prototyping', 'validation']
  });

  // Auto-include in future prototypes
}

Integration with Other Skills

Context Manager

Recalls tech stack:

Query for DECISION with tags: [tech-stack, framework]
Query for PREFERENCE with tags: [libraries, tools]
Apply to prototype generation

Saves validated patterns:

After user validates prototype
Save pattern as PROCEDURE
Tag with feature name and tech stack

Rapid Production Build

After validation:

User: "Build it properly"
→ Use validated prototype as reference
→ Add error handling
→ Add tests (via testing-builder)
→ Add proper styling
→ Add security measures
→ Create production version

Browser App Creator

For standalone tools:

If prototype should be standalone tool:
→ Invoke browser-app-creator
→ Convert prototype to polished single-file app
→ Save to artifacts/browser-apps/

Success Patterns

Quick Validation (5 minutes)

Scope: Single feature, visual feedback
Deliverable: Working demo
Example: "Does this button style work?"

<!DOCTYPE html>
<html>
<body>
  <button style="background: #3b82f6; color: white; padding: 12px 24px; border: none; border-radius: 8px; font-size: 16px; cursor: pointer;">
    Click Me
  </button>
</body>
</html>

Feature Prototype (15-30 minutes)

Scope: Complete feature with interactions
Deliverable: Multi-file app
Example: "User authentication flow"

See full auth prototype above.

Architecture Validation (30-60 minutes)

Scope: System design, integration points
Deliverable: Working system with multiple components
Example: "Microservices communication pattern"

// api-gateway.js
// orchestrator.js
// user-service.js
// Complete working system

Prototype Checklist

Before generating:
✅ Requirements clear
✅ Tech stack recalled
✅ Scope defined (minimal but complete)
✅ Success criteria established

While generating:
✅ Focus on happy path
✅ Make it runnable immediately
✅ Include clear instructions
✅ Use simple, obvious code

After generating:
✅ Test that it runs
✅ Verify success criteria met
✅ Provide clear next steps
✅ Ask for validation

Quick Reference

When to Prototype

Trigger Phrases

• "prototype this"
• "quick demo"
• "proof of concept"
• "can we build"
• "how would we"
• "test the idea"

File Locations

• Prototypes: ~/.claude-artifacts/prototypes/ (Linux/macOS) or %USERPROFILE%\.claude-artifacts\prototypes\ (Windows)
• Validated patterns: ~/.claude-memories/procedures/ (Linux/macOS) or %USERPROFILE%\.claude-memories\procedures\ (Windows) - tagged "prototype-validated"

Success Criteria

✅ Prototype runs immediately (no setup friction)
✅ Visually demonstrates the concept
✅ Tests core functionality
✅ Takes <30 minutes to create
✅ Clear README with instructions
✅ User can validate yes/no quickly