# Apple Health MCP Server

[![npm version](https://badge.fury.io/js/@neiltron%2Fapple-health-mcp.svg)](https://www.npmjs.com/package/@neiltron/apple-health-mcp)
[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)

Query Apple Health data from an MCP client using SQL and DuckDB. The server runs
locally, reads CSV exports on demand, and provides tools for schema discovery,
read-only queries, and health summaries.

## Requirements

- Node.js 22 or newer
- An Apple Health CSV export created with
  [Simple Health Export CSV](https://apps.apple.com/us/app/simple-health-export-csv/id1535380115)

The native Apple Health `export.xml` format is not currently supported.

## Configure an MCP client

For Claude Desktop, add the following to
`~/Library/Application Support/Claude/claude_desktop_config.json`:

```json
{
  "mcpServers": {
    "apple-health": {
      "command": "npx",
      "args": ["-y", "@neiltron/apple-health-mcp"],
      "env": {
        "HEALTH_DATA_DIR": "/path/to/your/unzipped/health-export"
      }
    }
  }
}
```

Restart the client after changing its configuration. Other MCP clients can use
the same command, arguments, environment, and `stdio` transport.

### Environment variables

| Variable | Required | Default | Purpose |
| --- | --- | --- | --- |
| `HEALTH_DATA_DIR` | Yes | — | Directory containing the exported CSV files |
| `MAX_MEMORY_MB` | No | `2048` | DuckDB memory limit in megabytes |
| `CACHE_SIZE` | No | `100` | Maximum number of cached query results |

## Export health data

1. Install and open Simple Health Export CSV on your iPhone.
2. Select **All** and choose the time range to export.
3. Transfer the archive to the computer running your MCP client.
4. Unzip it and set `HEALTH_DATA_DIR` to the resulting directory.

The server reads the files in place. It does not upload the export or make
network requests, although query results returned to your MCP client may be
sent to that client's configured model provider.

## Tools

| Tool | Purpose |
| --- | --- |
| `health_schema` | Discover table names, columns, units, and sample rows |
| `health_query` | Run a read-only `SELECT` query with JSON, CSV, or summary output |
| `health_report` | Generate a weekly, monthly, or custom health summary |

Start with `health_schema`; table names depend on the files in your export.
See [Querying Apple Health data](https://github.com/neiltron/apple-health-mcp/blob/main/docs/querying.md)
for the data model and working examples.

## History and memory

The first request that needs a table loads that table's full CSV history. There
is no date window, so a query can reach as far back as the export goes.

Because every tool can reach the whole configured history, only start this
server from an MCP client you trust with that data.

Loaded tables are held in memory, and DuckDB is given the `MAX_MEMORY_MB` limit
described above. Roughly 1 GiB covers a two-year multi-table export, so the
2048MB default leaves headroom; raise `MAX_MEMORY_MB` for a larger export. The
server never spills health rows to a temporary directory on disk, so an export
that does not fit in the limit fails with an explicit error instead.

Other current limitations:

- Only the Simple Health Export CSV layout is supported.
- The DuckDB database is in memory and is rebuilt for each server process, so
  each launch reloads from the CSV files. Persistent incremental import is
  planned future work, not current behavior.
- Device overlap can produce duplicate-looking measurements; queries should
  account for `sourceName` where appropriate.
- Health reports summarize recorded data and are not medical advice.

## Development

```bash
git clone https://github.com/neiltron/apple-health-mcp.git
cd apple-health-mcp
bun install

npm test
npm run typecheck
npm run build
```

See [Architecture](https://github.com/neiltron/apple-health-mcp/blob/main/docs/architecture.md)
for the code layout, data lifecycle, and implementation constraints.

## License

MIT