Crossroads

AI-powered social coordination. Friends connect Google Calendar and optionally share location; Claude analyzes availability overlaps, proximity, and activity preferences to generate meetup suggestions.

Stack

• Next.js 16 (App Router) + TypeScript
• Shadcn/ui + Tailwind CSS
• NextAuth v4 — Google OAuth with calendar.readonly + calendar.events scopes
• Prisma 7 + PostgreSQL (@prisma/adapter-pg)
• Claude API (claude-sonnet-4-6) via @anthropic-ai/sdk
• Google Calendar API (read for sync, write for confirmed meetups)

Setup

1. Environment

Copy and fill in .env.local:

DATABASE_URL=postgresql://...
NEXTAUTH_URL=http://localhost:3000
NEXTAUTH_SECRET=<openssl rand -base64 32>
GOOGLE_CLIENT_ID=...
GOOGLE_CLIENT_SECRET=...
ANTHROPIC_API_KEY=...

Google Cloud setup:

• Enable Calendar API and People API
• Add https://www.googleapis.com/auth/calendar.readonly and https://www.googleapis.com/auth/calendar.events to consent screen
• Add redirect URI: http://localhost:3000/api/auth/callback/google
• If you add calendar scopes after users have already signed in, they must reconnect Google once so their stored token is re-issued with the new permissions.

2. Database

npx prisma db push
npm run db:seed   # optional demo data

3. Run

npm run dev

How it works

1. Sign in with Google → tokens stored in DB
2. Settings → sync calendar → availability blocks computed
3. Settings → share location → proximity enabled
4. Settings → set activity preferences
5. Add friends, accept their requests
6. Dashboard → AI pipeline runs:
   • Loads availability blocks for user + friends (next 48h)
   • Computes pairwise overlapping free windows
   • Scores clusters by proximity × activity overlap
   • Sends top 10 clusters to Claude as structured context
   • Claude returns JSON array of suggestions
   • Suggestions persisted (cached 4h)
7. Confirm a suggestion → creates a Meetup record

Project structure

src/
├── app/
│   ├── page.tsx              # Landing / auth gate
│   ├── dashboard/page.tsx    # Suggestion feed + upcoming meetups
│   ├── friends/page.tsx      # Friend management
│   ├── groups/page.tsx       # Group management
│   ├── settings/page.tsx     # Calendar, location, preferences
│   └── api/                  # All API routes
├── components/               # UI components by domain
├── lib/
│   ├── matching.ts           # Algorithmic candidate clustering
│   ├── claude.ts             # Claude prompt + response parsing
│   ├── availability.ts       # Free-block computation
│   └── google-calendar.ts    # Calendar API + token refresh
└── types/index.ts