MCP Glucose Server

import express from 'express'; import { Server } from '@modelcontextprotocol/sdk/server/index.js'; import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js'; import { CallToolRequestSchema, ListToolsRequestSchema, Tool, } from '@modelcontextprotocol/sdk/types.js'; import { HealthDataAPI } from './api-client.js'; import dotenv from 'dotenv'; // Load environment variables dotenv.config(); // Configuration const STORAGE_API_URL = process.env.STORAGE_API_URL || ''; const API_SECRET = process.env.API_SECRET || ''; const DEFAULT_USER_ID = process.env.USER_ID || ''; if (!STORAGE_API_URL || !API_SECRET) { console.error('❌ Error: STORAGE_API_URL and API_SECRET environment variables are required'); process.exit(1); } // Initialize API client const api = new HealthDataAPI(STORAGE_API_URL, API_SECRET); // Define available tools const TOOLS: Tool[] = [ { name: 'search', description: 'Search through glucose/blood sugar readings. Query can include date ranges or natural language.', inputSchema: { type: 'object', properties: { query: { type: 'string', description: 'Search query for glucose data. Can include keywords like "today", "yesterday", ' + '"last week", "last 30 days", or specific dates.', }, userId: { type: 'string', description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`, }, }, required: ['query'], }, }, { name: 'fetch', description: 'Retrieve complete details for a specific glucose reading by ID. ' + 'Use this after finding readings with the search tool.', inputSchema: { type: 'object', properties: { id: { type: 'string', description: 'The unique identifier for the reading. Format: "reading:timestamp" ' + '(e.g., "reading:2024-01-15T10:30:00Z")', }, userId: { type: 'string', description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`, }, }, required: ['id'], }, }, { name: 'get_glucose_readings', description: 'Get glucose/blood sugar readings for a user within a date range. Returns glucose values in mg/dL with timestamps and sources.', inputSchema: { type: 'object', properties: { userId: { type: 'string', description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`, }, startDate: { type: 'string', description: 'Start date in ISO 8601 format (e.g., 2025-10-01T00:00:00Z). Optional.', }, endDate: { type: 'string', description: 'End date in ISO 8601 format (e.g., 2025-10-22T23:59:59Z). Optional.', }, limit: { type: 'number', description: 'Maximum number of readings to return (default: 1000)', }, }, required: [], }, }, { name: 'get_latest_glucose', description: 'Get the most recent glucose/blood sugar reading for a user. Returns value, unit, timestamp, and source.', inputSchema: { type: 'object', properties: { userId: { type: 'string', description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`, }, }, required: [], }, }, { name: 'get_glucose_stats', description: 'Get glucose statistics (count, average, min, max) for a user within a date range. Useful for understanding glucose trends and patterns.', inputSchema: { type: 'object', properties: { userId: { type: 'string', description: `User identifier. Defaults to ${DEFAULT_USER_ID || 'configured user'} if not specified.`, }, startDate: { type: 'string', description: 'Start date in ISO 8601 format. Optional.', }, endDate: { type: 'string', description: 'End date in ISO 8601 format. Optional.', }, }, required: [], }, }, ]; // Create ONE MCP server instance (reused for all sessions) const server = new Server( { name: 'mcp-glucose', version: '1.0.0', }, { capabilities: { tools: {}, }, } ); // Helper function to parse date queries for glucose function parseGlucoseDateQuery(query: string): { startDate?: string; endDate?: string } { const now = new Date(); const lowerQuery = query.toLowerCase(); if (lowerQuery.includes('today')) { const today = new Date(now.getFullYear(), now.getMonth(), now.getDate()); return { startDate: today.toISOString(), endDate: now.toISOString() }; } if (lowerQuery.includes('yesterday')) { const yesterday = new Date(now.getTime() - 24 * 60 * 60 * 1000); const yesterdayStart = new Date( yesterday.getFullYear(), yesterday.getMonth(), yesterday.getDate() ); const yesterdayEnd = new Date(yesterdayStart.getTime() + 24 * 60 * 60 * 1000); return { startDate: yesterdayStart.toISOString(), endDate: yesterdayEnd.toISOString() }; } const lastDaysMatch = lowerQuery.match(/last (\d+) days?/); if (lastDaysMatch) { const days = parseInt(lastDaysMatch[1]); const start = new Date(now.getTime() - days * 24 * 60 * 60 * 1000); return { startDate: start.toISOString(), endDate: now.toISOString() }; } const lastWeekMatch = lowerQuery.match(/last week/); if (lastWeekMatch) { const start = new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000); return { startDate: start.toISOString(), endDate: now.toISOString() }; } // Default to last 7 days const start = new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000); return { startDate: start.toISOString(), endDate: now.toISOString() }; } // Register tool handlers ONCE server.setRequestHandler(ListToolsRequestSchema, async () => { return { tools: TOOLS, }; }); server.setRequestHandler(CallToolRequestSchema, async (request) => { const { name, arguments: args } = request.params; const userId = (args?.userId as string) || DEFAULT_USER_ID; if (!userId) { return { content: [ { type: 'text', text: 'Error: userId is required. Either provide it in the tool call or set USER_ID environment variable.', }, ], isError: true, }; } try { switch (name) { case 'search': { const query = args?.query as string; if (!query) { throw new Error('Query parameter is required'); } console.log(`🔍 Executing search with query: "${query}"`); const { startDate, endDate } = parseGlucoseDateQuery(query); const readings = await api.getGlucoseReadings({ userId, startDate, endDate, limit: 100, }); // Format results for Deep Research const results: any[] = []; readings.forEach((reading) => { const date = new Date(reading.date); results.push({ id: `reading:${reading.date}`, title: `Glucose: ${reading.value} ${reading.unit}`, text: `Glucose reading of ${reading.value} ${reading.unit} on ${date.toLocaleDateString()} at ${date.toLocaleTimeString()}. Source: ${reading.source}`, url: 'https://healthmate.app', }); }); console.log(`✅ Search completed successfully. Found ${results.length} results`); return { content: [ { type: 'text', text: JSON.stringify({ results }, null, 2), }, ], }; } case 'fetch': { const id = args?.id as string; if (!id) { throw new Error('ID parameter is required'); } console.log(`📥 Executing fetch with id: "${id}"`); const [type, timestamp] = id.split(':'); if (type !== 'reading') { throw new Error(`Unknown type: ${type}`); } // Get readings around that timestamp const targetDate = new Date(timestamp); const startDate = new Date(targetDate.getTime() - 1 * 60 * 60 * 1000); // 1 hour before const endDate = new Date(targetDate.getTime() + 1 * 60 * 60 * 1000); // 1 hour after const readings = await api.getGlucoseReadings({ userId, startDate: startDate.toISOString(), endDate: endDate.toISOString(), limit: 100, }); const reading = readings.find((r) => r.date === timestamp); if (!reading) { throw new Error(`Reading not found for ID: ${id}`); } const result = { id, title: `Glucose: ${reading.value} ${reading.unit}`, text: JSON.stringify( { value: reading.value, unit: reading.unit, date: reading.date, source: reading.source, }, null, 2 ), url: 'https://healthmate.app', metadata: { type: 'glucose_reading', retrieved_at: new Date().toISOString(), }, }; console.log(`✅ Fetch completed successfully`); return { content: [ { type: 'text', text: JSON.stringify(result, null, 2), }, ], }; } case 'get_glucose_readings': { console.log(`📊 Fetching glucose readings for user: ${userId}`); const readings = await api.getGlucoseReadings({ userId, startDate: args?.startDate as string | undefined, endDate: args?.endDate as string | undefined, limit: (args?.limit as number) || 1000, }); console.log(`✅ Found ${readings.length} glucose readings`); return { content: [ { type: 'text', text: JSON.stringify( { count: readings.length, readings: readings.map((r) => ({ value: r.value, unit: r.unit, date: r.date, source: r.source, })), }, null, 2 ), }, ], }; } case 'get_latest_glucose': { console.log(`📊 Fetching latest glucose for user: ${userId}`); const reading = await api.getLatestGlucose(userId); if (!reading) { return { content: [ { type: 'text', text: 'No glucose readings found for this user.', }, ], }; } console.log(`✅ Latest glucose: ${reading.value} ${reading.unit}`); return { content: [ { type: 'text', text: JSON.stringify( { value: reading.value, unit: reading.unit, date: reading.date, source: reading.source, }, null, 2 ), }, ], }; } case 'get_glucose_stats': { console.log(`📊 Fetching glucose stats for user: ${userId}`); const stats = await api.getGlucoseStats({ userId, startDate: args?.startDate as string | undefined, endDate: args?.endDate as string | undefined, }); if (!stats) { return { content: [ { type: 'text', text: 'No glucose data found for the specified time range.', }, ], }; } console.log(`✅ Glucose stats: avg ${stats.average} ${stats.unit}`); return { content: [ { type: 'text', text: JSON.stringify(stats, null, 2), }, ], }; } default: throw new Error(`Unknown tool: ${name}`); } } catch (error: any) { console.error('❌ Error calling tool:', error); return { content: [ { type: 'text', text: `Error: ${error.message}`, }, ], isError: true, }; } }); // Set up Express server const app = express(); // Don't parse JSON for /message - SSEServerTransport handles it app.use((req, res, next) => { if (req.path === '/message') { next(); } else { express.json()(req, res, next); } }); const PORT = process.env.PORT || 8080; const HOST = process.env.HOST || '0.0.0.0'; // Store transports by sessionId for multi-session support const transports: Map<string, SSEServerTransport> = new Map(); // SSE endpoint - IMPORTANT: No trailing slash for ChatGPT compatibility app.get('/sse', async (_req, res) => { console.log('SSE client connected'); // Create SSE transport - it will generate its own sessionId const transport = new SSEServerTransport('/message', res); // Use the transport's own sessionId const sessionId = (transport as any).sessionId; console.log(`Established SSE stream with session ID: ${sessionId}`); // Store transport by its sessionId transports.set(sessionId, transport); console.log(`Transport stored for session: ${sessionId} (total transports: ${transports.size})`); // Set up close handler (transport as any).onclose = () => { console.log(`SSE transport closed for session ${sessionId}`); transports.delete(sessionId); console.log(`Transport removed (total transports: ${transports.size})`); }; // Connect the transport to the MCP server await server.connect(transport); }); // POST /message handler - forwards messages to correct session app.post('/message', async (req, res) => { console.log('Received POST to /message'); // Extract session ID from URL query parameter const sessionId = req.query.sessionId as string; if (!sessionId) { console.error('No session ID provided in request URL'); res.status(400).send('Missing sessionId parameter'); return; } console.log(`Looking for transport with sessionId: ${sessionId}`); console.log(`Available sessions: ${Array.from(transports.keys()).join(', ')}`); const transport = transports.get(sessionId); if (!transport) { console.error(`No active transport found for session ID: ${sessionId}`); res.status(404).json({ error: 'Session not found', sessionId, availableSessions: Array.from(transports.keys()), }); return; } try { console.log(`Found transport for session: ${sessionId}, forwarding message`); // CRITICAL: Pass 3 parameters - req, res, AND req.body // This is the working pattern from whoop-mcp-server await transport.handlePostMessage(req, res, req.body); console.log(`Message handled successfully for session: ${sessionId}`); } catch (error) { console.error(`Error handling message for session ${sessionId}:`, error); if (!res.headersSent) { res.status(500).json({ error: 'Internal server error' }); } } }); // Health check endpoint app.get('/health', (_req, res) => { res.json({ status: 'ok', service: 'mcp-glucose', timestamp: new Date().toISOString(), storage_api: STORAGE_API_URL, }); }); // List tools endpoint (for debugging) app.get('/tools', (_req, res) => { res.json({ tools: TOOLS, }); }); // Start server app.listen(PORT, () => { console.log(`🩸 Glucose MCP Server listening on port ${PORT}`); console.log(`📊 Health check: http://${HOST}:${PORT}/health`); console.log(`🔌 SSE endpoint: http://${HOST}:${PORT}/sse`); console.log(`📡 Connected to storage API: ${STORAGE_API_URL}`); console.log(`👤 Default user: ${DEFAULT_USER_ID || '(none - must specify in tool calls)'}`); });