Health4AI

Ask your AI about your sleep, HRV, recovery, and fitness — in plain language.
Free iOS app · Your own database · Works with any MCP client

What it does

iPhone HealthKit → Your Postgres database → MCP server → Any AI

Apple Health holds years of your biometric data — sleep stages, HRV, heart rate, workouts, VO₂ max, and 150+ other metrics. health4.ai makes all of it queryable from Claude, ChatGPT, Cursor, Ollama, or any MCP-compatible client via 8 purpose-built tools.

You control the data. It syncs to a Postgres database you configure — Supabase, Neon, or a local Docker container. health4.ai never stores or has access to your health data.

Why it exists

Demo

Demo video coming. Here's what a typical conversation looks like:

You:     How was my recovery this week? Anything standing out?

Claude:  Your recovery this week was mixed but trending positive.
         • HRV averaged 58ms (Tue–Thu strong at 64–68ms; Monday low at 44ms after Saturday's long run)
         • Sleep averaged 7h 12m — Wednesday and Thursday were your best nights (7h 40m+)
         • Resting HR dropped from 54bpm Monday to 49bpm Friday — a good sign
         Recommendation: today looks like a solid day for a moderate-intensity session.

Quick start

Choose your Postgres backend first:

# 1. Create a project at supabase.com
# 2. Run the schema
psql "$DATABASE_URL" < web/public/schema.sql
# or use the Supabase dashboard SQL editor

# 1. Create a project at neon.tech
# 2. Run the schema
psql "$DATABASE_URL" < web/public/schema.sql

docker run -d \
  --name health4ai-postgres \
  -e POSTGRES_PASSWORD=yourpassword \
  -p 5432:5432 \
  postgres:16
psql "postgresql://postgres:yourpassword@localhost:5432/postgres" \
  < web/public/schema.sql

Then set up the MCP server:

git clone https://github.com/jefflitt1/health4ai.git
cd health4ai

cp mcp-server/.env.example mcp-server/.env

Edit mcp-server/.env:

DATABASE_URL=postgresql://...    # your Postgres connection string
HEALTHKIT_USER_ID=your_user_id   # any string to identify your data

Add to your AI client:

{
  "mcpServers": {
    "health4ai": {
      "command": "python",
      "args": ["/path/to/health4ai/mcp-server/main.py"],
      "env": {
        "DATABASE_URL": "postgresql://...",
        "HEALTHKIT_USER_ID": "your_user_id"
      }
    }
  }
}

mcphost --model ollama/llama3.2 \
  --mcp-server "health4ai:python /path/to/health4ai/mcp-server/main.py"

Install the iOS app: TestFlight link coming at App Store launch. Sign in with your database credentials and tap Start Sync.

MCP tools

Architecture

┌─────────────────────────────────────────────────────────────┐
│  iPhone                                                      │
│  HKObserverQuery + BGTaskScheduler                          │
│  → continuous background sync                               │
└──────────────────────────┬──────────────────────────────────┘
                           │ HTTPS
                           ▼
┌─────────────────────────────────────────────────────────────┐
│  Your Postgres database (Supabase / Neon / local Docker)    │
│  healthkit_metrics · healthkit_daily_summaries              │
│  v_healthkit_daily_quantity (unified view)                  │
└──────────────────────────┬──────────────────────────────────┘
                           │ SQL (service-role key, server-side only)
                           ▼
┌─────────────────────────────────────────────────────────────┐
│  FastMCP server  (mcp-server/main.py)                       │
│  11 tools · stdio transport                                  │
└──────────────────────────┬──────────────────────────────────┘
                           │ MCP
                           ▼
              Claude · ChatGPT · Cursor · Ollama · any client

Data tiers: queries within the last 30 days return raw samples; older data transparently switches to pre-aggregated daily summaries — so long-term trend queries stay fast regardless of data volume.

Repo structure

health4ai/
├── ios/                         # Swift/SwiftUI iOS app (iOS 17+)
│   └── Health4AI/               # HealthKit sync engine, auth, settings
├── mcp-server/
│   ├── main.py                  # FastMCP server entry point
│   ├── tools.py                 # 11 tool implementations
│   └── .env.example             # Required environment variables
├── web/
│   ├── public/schema.sql        # Portable Postgres schema (all backends)
│   └── src/                     # Astro marketing site
├── scripts/
│   ├── import_health_export.py  # One-time XML backfill from Apple Health export
│   └── summarize_historical.py  # Backfill daily summaries table
└── docs/
    └── SETUP.md                 # Detailed setup guide

Privacy

Your health data goes directly from your iPhone to your Postgres database. health4.ai never receives, stores, or has access to it. The MCP server runs locally with your own credentials — your data never touches our infrastructure.

See the Privacy Policy for full details.

Contributing

MIT licensed. PRs welcome.

Good first areas: additional metric aggregations, multi-user support with JWT/RLS, Android, and more MCP client integration guides.

License

MIT — see LICENSE.