MCP Glucose Server

A Model Context Protocol (MCP) server that provides glucose data query tools to AI assistants like Claude and ChatGPT. Connects to the health-data-storage API to retrieve glucose readings.

🎯 Purpose

This MCP server acts as a specialized interface between AI assistants and your glucose data. It provides natural language tools for querying glucose levels, trends, and statistics.

🏗️ Architecture Position

┌──────────────────────┐
│ health-data-storage  │
│  REST API            │
└──────────┬───────────┘
           │ HTTP GET
           ▼
    ┌──────────────┐
    │ mcp-glucose  │  ← YOU ARE HERE
    │ (MCP Server) │
    └──────┬───────┘
           │ MCP Tools
           ▼
   ┌───────────────┐
   │ Claude/ChatGPT│
   └───────────────┘

🔧 Available Tools

1. get_glucose_readings

Get glucose readings within a date range.

Parameters:

• userId (optional): User identifier (defaults to USER_ID env var)
• startDate (optional): Start date in ISO 8601 format
• endDate (optional): End date in ISO 8601 format
• limit (optional): Maximum number of readings (default: 1000)

Example queries:

• "What's my glucose been like today?"
• "Show me my glucose readings for the past week"
• "Get my glucose levels from October 1st to October 22nd"

2. get_latest_glucose

Get the most recent glucose reading.

Parameters:

• userId (optional): User identifier (defaults to USER_ID env var)

Example queries:

• "What's my current glucose?"
• "What was my last glucose reading?"
• "Check my latest blood sugar"

3. get_glucose_stats

Get glucose statistics (count, average, min, max) for a time period.

Parameters:

• userId (optional): User identifier (defaults to USER_ID env var)
• startDate (optional): Start date in ISO 8601 format
• endDate (optional): End date in ISO 8601 format

Example queries:

• "What's my average glucose this week?"
• "Show me my glucose stats for the past month"
• "What was my glucose range yesterday?"

🚀 Setup

Prerequisites

• Node.js 20+
• Access to a deployed health-data-storage instance
• API secret for authentication

Installation

# Install dependencies
npm install

# Build TypeScript
npm run build

Configuration

Create a .env file (or set environment variables):

STORAGE_API_URL=https://your-storage-api.run.app
API_SECRET=your-api-secret
USER_ID=user@example.com  # Optional default user

Usage with Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "glucose": {
      "command": "node",
      "args": ["/path/to/mcp-glucose/build/index.js"],
      "env": {
        "STORAGE_API_URL": "https://your-storage-api.run.app",
        "API_SECRET": "your-api-secret",
        "USER_ID": "user@example.com"
      }
    }
  }
}

Restart Claude Desktop.

Usage with ChatGPT

(ChatGPT MCP support coming soon)

💬 Example Conversations

Once configured, you can ask Claude:

Simple queries:

"What's my latest glucose?"

{
  "value": 95,
  "unit": "mg/dL",
  "date": "2025-10-22T10:30:00Z",
  "source": "Lingo"
}

Time range queries:

"Show me my glucose for the past 24 hours"

{
  "count": 48,
  "readings": [
    { "value": 95, "unit": "mg/dL", "date": "2025-10-22T10:30:00Z", "source": "Lingo" },
    ...
  ]
}

Statistical queries:

"What's my average glucose this week?"

{
  "count": 336,
  "average": 98.5,
  "min": 75,
  "max": 125,
  "unit": "mg/dL"
}

Analysis queries:

"Analyze my glucose patterns over the last month"

Claude will use the tools to fetch data and provide intelligent analysis of your glucose trends, patterns, and insights.

🔗 Related Projects

• health-data-storage: Storage backend that this server queries
• health-tracking-app: iOS app that collects the glucose data
• mcp-activity: (future) MCP server for activity/exercise data
• mcp-nutrition: (future) MCP server for food/nutrition data

📈 Future Enhancements

Potential additions:

• Trend analysis tools: Detect glucose spikes, patterns
• Correlation tools: Compare glucose with meals, exercise
• Alert tools: Notify when glucose is out of range
• Export tools: Generate reports, charts
• Multi-user support: Query data for multiple users

🛠️ Development

Local Testing

# Build
npm run build

# Run (will use stdio transport)
npm start

The server runs on stdio (standard input/output) as per MCP specification. Use it with Claude Desktop or the MCP inspector for testing.

Testing with MCP Inspector

npm install -g @modelcontextprotocol/inspector
npx @modelcontextprotocol/inspector node build/index.js

📝 License

MIT