Dexcom Server

A Model Context Protocol (MCP) server that connects Claude to your personal Dexcom CGM (Continuous Glucose Monitor) for assistive diabetes management intelligence.

🎯 Prime Directive

This is a human-in-the-loop assistive intelligence system:

• ✅ Claude analyzes, reasons, and recommends
• ✅ User decides and acts
• ❌ No automation, no control, no silent changes

🚀 Features

• Real-time CGM Data: Fetch current and historical glucose readings
• Trend Analysis: Analyze patterns, post-meal spikes, and overnight stability
• Event Logging: Track insulin doses, carbohydrate intake, and exercise
• Adaptive Modeling: Learn how your metabolism behaves over time
• Predictive Intelligence: Estimate glucose impact of insulin and carbs
• Visualizations: Generate charts and AGP (Ambulatory Glucose Profile)
• Parameter Drift Detection: Identify when your insulin sensitivity changes

📋 Prerequisites

• Node.js 18+
• Dexcom Developer API credentials (apply here)
• A Dexcom CGM device actively transmitting data

🔧 Installation

1. Clone this repository:

   git clone https://github.com/cykj40/dexcom-mcp-server.git
   cd dexcom-mcp-server
   

2. Install dependencies:

   npm install
   

3. Configure environment variables:

   cp .env.example .env
   

   Edit .env and fill in your credentials:

   • DEXCOM_CLIENT_ID - From Dexcom Developer Portal
   • DEXCOM_CLIENT_SECRET - From Dexcom Developer Portal
   • DEXCOM_REDIRECT_URI - OAuth redirect URI
   • TURSO_DATABASE_URL - Turso database URL for token and glucose persistence
   • DEXCOM_ACCESS_TOKEN / DEXCOM_REFRESH_TOKEN - Optional one-time bootstrap only when Turso has no tokens

4. Build the project:

   npm run build
   

🎮 Usage

Running the Server Directly

npm start

Integrating with Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "dexcom": {
      "command": "node",
      "args": ["/absolute/path/to/dexcom-mcp-server/dist/index.js"],
      "env": {
        "DEXCOM_CLIENT_ID": "your_client_id",
        "DEXCOM_CLIENT_SECRET": "your_client_secret",
        "DEXCOM_REDIRECT_URI": "your_redirect_uri",
        "TURSO_DATABASE_URL": "libsql://your-db.turso.io",
        "TURSO_AUTH_TOKEN": "your_turso_auth_token"
      }
    }
  }
}

Restart Claude Desktop, and you'll have access to all Dexcom tools.

🛠️ Available Tools

Glucose Reading Tools

• get_latest_glucose - Get current glucose with trend
• get_glucose_range - Get readings within a time range
• get_daily_summary - Daily glucose statistics
• get_glucose_statistics - Comprehensive stats for any period

Analysis Tools

• analyze_trends - Analyze patterns over days/weeks
• compare_expected_vs_actual - Compare predictions to reality
• detect_parameter_drift - Identify if ISF/ICR has changed

Event Logging Tools

• log_insulin - Log insulin dose
• log_carbs - Log carbohydrate intake
• log_exercise - Log physical activity
• get_event_timeline - View all events with glucose context

Chart Tools

• generate_chart - Create visualizations (timeline, daily, weekly, AGP)

Modeling Tools

• get_baseline_parameters - View your ISF, ICR, and basal dose
• predict_glucose_impact - Predict effect of insulin or carbs
• get_adaptive_insights - See how predictions compare to reality

📊 Database

All data is stored locally in SQLite at ./data/dexcom.db:

• Glucose readings (from Dexcom API and Share API)
• Insulin, carb, and exercise events
• Adaptive observations (expected vs actual outcomes)

No data is shared with third parties.

🔒 Security

• Environment variables only: Never hardcode credentials
• Local storage: All data stays on your machine
• OAuth 2.0: Uses official Dexcom Developer API
• Read-only device access: Cannot modify pump settings

🏥 Medical Disclaimer

This is an assistive tool, not medical advice.

• All recommendations are based on your personal data
• You are the final authority on all diabetes management decisions
• Never rely solely on this tool for treatment decisions
• Consult your healthcare provider before changing insulin doses
• This is not FDA-approved medical software

🧪 Development

Run in Development Mode

npm run dev

Build

npm run build

Project Structure

dexcom-mcp-server/
├── src/
│   ├── config/         # Environment validation
│   ├── db/             # SQLite database layer
│   ├── services/       # Business logic
│   ├── tools/          # MCP tool definitions
│   ├── types/          # TypeScript types
│   └── index.ts        # Server entrypoint
├── data/               # SQLite database (gitignored)
└── dist/               # Compiled JavaScript

📝 License

ISC License - See LICENSE file for details

🤝 Contributing

This is a personal diabetes management tool. If you'd like to adapt it for your own use:

1. Update baseline parameters in src/types/index.ts
2. Adjust target ranges if needed
3. Modify modeling algorithms to match your physiology

📧 Support

For issues or questions, please open a GitHub issue.

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Remember: This tool learns from your patterns but never acts autonomously. You decide, you act, you control.