get_glucose_stats

Instructions

Implementation Reference

• src/index.ts:110-126 (registration)

  Tool definition/registration for 'get_glucose_stats' in the tools array, with name, description, and inputSchema (accepts optional 'days' parameter).

  {
    name: 'get_glucose_stats',
    description: 'Calculate comprehensive glucose statistics including average glucose, GMI (estimated A1C), time-in-range percentages, and variability metrics. Essential for diabetes management insights and identifying areas for improvement.',
    inputSchema: {
      type: 'object',
      properties: {
        days: {
          type: 'number',
          description: 'Number of days to analyze (1-14). Default: 7. Note: LibreLinkUp data availability may be limited.'
        }
      },
      required: []
    },
    annotations: {
      readOnlyHint: true
    }
  },

• src/index.ts:294-323 (handler)

  Handler in CallToolRequestSchema that executes 'get_glucose_stats': fetches glucose history for N days, calls analytics.calculateGlucoseStats(), and returns structured JSON with average glucose, GMI, time-in-range percentages, and variability metrics.

  case 'get_glucose_stats': {
    if (!client || !analytics) {
      throw new Error('LibreLinkUp not configured. Use configure_credentials first.');
    }
  
    const days = (args?.days as number) || 7;
    const readings = await client.getGlucoseHistory(days * 24);
    const stats = analytics.calculateGlucoseStats(readings);
  
    return {
      content: [{
        type: 'text',
        text: JSON.stringify({
          analysis_period_days: days,
          average_glucose: stats.average,
          glucose_management_indicator: stats.gmi,
          time_in_range: {
            target_70_180: stats.timeInRange,
            below_70: stats.timeBelowRange,
            above_180: stats.timeAboveRange
          },
          variability: {
            standard_deviation: stats.standardDeviation,
            coefficient_of_variation: stats.coefficientOfVariation
          },
          reading_count: stats.readingCount
        }, null, 2)
      }]
    };
  }

• src/glucose-analytics.ts:19-71 (helper)

  Core implementation: calculateGlucoseStats() method on GlucoseAnalytics class. Computes average, standard deviation, coefficient of variation, GMI (3.31 + 0.02392*mean), time-in-range percentages based on configurable targetLow/targetHigh thresholds.

  calculateGlucoseStats(readings: GlucoseReading[]): GlucoseStats {
    if (readings.length === 0) {
      return {
        average: 0,
        gmi: 0,
        timeInRange: 0,
        timeBelowRange: 0,
        timeAboveRange: 0,
        standardDeviation: 0,
        coefficientOfVariation: 0,
        readingCount: 0
      };
    }
  
    const values = readings.map(r => r.value);
    const n = values.length;
  
    // Calculate average
    const sum = values.reduce((a, b) => a + b, 0);
    const average = sum / n;
  
    // Calculate standard deviation
    const squaredDiffs = values.map(v => Math.pow(v - average, 2));
    const avgSquaredDiff = squaredDiffs.reduce((a, b) => a + b, 0) / n;
    const standardDeviation = Math.sqrt(avgSquaredDiff);
  
    // Calculate coefficient of variation
    const coefficientOfVariation = (standardDeviation / average) * 100;
  
    // Calculate GMI (Glucose Management Indicator)
    // GMI = 3.31 + 0.02392 × [mean glucose in mg/dL]
    const gmi = 3.31 + (0.02392 * average);
  
    // Calculate time in range
    const inRange = values.filter(v => v >= this.config.targetLow && v <= this.config.targetHigh).length;
    const belowRange = values.filter(v => v < this.config.targetLow).length;
    const aboveRange = values.filter(v => v > this.config.targetHigh).length;
  
    const timeInRange = (inRange / n) * 100;
    const timeBelowRange = (belowRange / n) * 100;
    const timeAboveRange = (aboveRange / n) * 100;
  
    return {
      average: Math.round(average * 100) / 100,
      gmi: Math.round(gmi * 100) / 100,
      timeInRange: Math.round(timeInRange * 100) / 100,
      timeBelowRange: Math.round(timeBelowRange * 100) / 100,
      timeAboveRange: Math.round(timeAboveRange * 100) / 100,
      standardDeviation: Math.round(standardDeviation * 100) / 100,
      coefficientOfVariation: Math.round(coefficientOfVariation * 100) / 100,
      readingCount: n
    };
  }

• src/types.ts:34-43 (schema)

  GlucoseStats interface defining the return type shape: average, gmi, timeInRange, timeBelowRange, timeAboveRange, standardDeviation, coefficientOfVariation, readingCount.

  export interface GlucoseStats {
    average: number;
    gmi: number;
    timeInRange: number;
    timeBelowRange: number;
    timeAboveRange: number;
    standardDeviation: number;
    coefficientOfVariation: number;
    readingCount: number;
  }