Capstone: Build a Real Application

What This Capstone Tests

This is not a quiz — it is a build. You will use everything from all four levels: effective prompting (Level 0), understanding Claude's capabilities (Level 1), real-world tools (Level 2), and advanced techniques (Level 3). By the end you will have a live application at a real URL, built entirely by directing Claude.

Pick Your App

Choose one of the three ideas below — each uses the full free-tier stack from Lesson 27 and showcases real Claude capabilities. Or bring your own idea and use these as a template for how to structure your approach.

💡 App Idea 1: Personal Knowledge Base + AI Q&A

What it does: A private app where you paste articles, notes, and links. You can then ask questions in plain English and Claude searches your notes to answer them.

Stack

• Next.js + Tailwind hosted on Vercel
• Supabase (PostgreSQL + pgvector for semantic search)
• Supabase Auth (only you can access)
• Anthropic API (Haiku for tagging, Sonnet for answers)

Key Features

Build a personal knowledge base app called "Second Brain" 
with Next.js and Supabase.

1. Auth: Supabase email auth — only I can sign in
2. Note entry: textarea for pasting text. On save:
   - Claude (Haiku) generates a 2-sentence summary and 3 tags
   - Store in: notes(id, content, summary, tags, embedding, created_at)
   - Generate embedding via Anthropic API and store in pgvector column
3. Search: semantic search using pgvector similarity
4. Q&A page: input → find top 5 relevant notes → send to Claude Sonnet
   with those notes as context → stream the answer
5. Deploy on Vercel with env vars:
   NEXT_PUBLIC_SUPABASE_URL, NEXT_PUBLIC_SUPABASE_ANON_KEY, ANTHROPIC_API_KEY

Start with the database schema, then the note entry UI.

💡 App Idea 2: Smart Habit Tracker with Weekly AI Coaching

What it does: Track daily habits with a tap. Every Sunday, Claude analyses your week, spots patterns, and sends you a personalised coaching email.

Stack

• Next.js + Tailwind on Vercel
• Supabase (habits + daily logs)
• Clerk auth (free up to 10K users)
• Resend (weekly coaching email)
• Vercel Cron (runs every Sunday 8am)
• Anthropic API (analysis + coaching)

Key Features

Build a habit tracker app called "Momentum" with Next.js,
Supabase, and Clerk auth.

Database:
- habits(id, user_id, name, category, target_days_per_week, created_at)
- habit_logs(id, habit_id, user_id, completed_date, created_at)

Pages:
1. /dashboard — today's habits as a checklist (tap to complete)
2. /habits — manage habits (add/edit/delete)  
3. /stats — 12-week grid per habit (GitHub contribution style)

Weekly coaching (Vercel Cron, every Sunday 8am UTC):
- API route POST /api/weekly-coach
- Pull last 7 days of logs for the user
- Send to Claude: completion rates, best/worst habits, streaks
- Claude returns a 3-paragraph coaching message
- Send email via Resend to user's email

Start with database schema, then the dashboard.

💡 App Idea 3: AI Meeting Prep & Follow-Up Tool

What it does: Before a meeting, paste the agenda and attendees — Claude drafts talking points. After the meeting, paste your notes — Claude extracts action items, decisions, and drafts a follow-up email.

Stack

• Next.js + Tailwind on Vercel
• Supabase (meeting history + auth)
• Resend (follow-up emails)
• Anthropic API (prep + follow-up generation)

Key Features

Build a meeting prep app called "Brief" with Next.js and Supabase.

Database:
meetings(id, user_id, title, meeting_date, attendees jsonb,
         agenda text, prep_output text, notes text,
         structured_output jsonb, followup_email text, created_at)

Flow 1 — Pre-meeting prep:
- Form: title, date, attendees (name + company), agenda topics
- Call Anthropic API: generate 3 talking points + 2 questions per
  agenda topic, and what each attendee likely cares about
- Display and save to database

Flow 2 — Post-meeting follow-up:
- Textarea for raw notes
- Extract: decisions[], action_items[{task, owner, due}], open_questions[]
- Draft follow-up email (3 paragraphs, professional tone)
- Show structured output + email draft side-by-side
- "Copy email" button

List all meetings at /meetings (title, date, attendee count).
Start with the database schema and pre-meeting flow.

How to Run Your Capstone Build

I'm building [app name] with Next.js 14 App Router, TypeScript,
Tailwind CSS, and Supabase.

Generate a project CLAUDE.md covering:
- Tech stack and versions
- Database tables (I'll share schema once built)
- Code style: strict TypeScript, no any, Zod for validation
- File structure conventions
- Patterns to keep consistent across the codebase

Stuck? Prompts That Unblock

Here is the TypeScript error: [paste error]
Here is the file: [paste file]
Fix the error. Explain what caused it in one sentence.

Expected: [describe]
Actual: [describe]
Relevant code: [paste]
Debug this step by step.

I have [A] working and [B] working separately.
I need [A] to trigger [B] when [condition].
Show me the minimal code to wire these together.

Course Complete 🎉

If you have built and deployed your capstone, you have done something most daily Claude users have never done. You understand the full stack — from writing a precise prompt to shipping a production application. You know the pitfalls, the tools, the ecosystem, and the techniques.