GitHub - neiltron/apple-health-mcp: MCP server for querying Apple Health data with natural language and SQL

GitHub

3 min read Original article ↗

npm version License: 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

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:

{
  "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 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

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 for the code layout, data lifecycle, and implementation constraints.

License

MIT